I vote for letting them sneak around. I am not going to encourage it. I will provide members of opposite sex a separate bedroom if staying at my house. But I am not going to patrol the hallways and such!
So will adults.
Why do you think that so many divorced moms with custody of their children insist that their kids spend the weekend with Dad? (And don’t feel sorry for Dad. Since he’s child-free during the week, he has opportunities of his own.)
When I graduated from college, I went to France for a year after, and came home happy but broke. I lived with my parents for six months while I got on my feet financially. NO WAY I would have been having sex with my longtime boyfriend in that house. For one, it’s a small house. Two, there were two very young siblings still living there. And three, I would have found that very awkward even if my parents had been okay with it (they would not have).
We found a way occasionally to be together (he was living at home for the same reasons), but it REALLY cramped my style (not just the romantic stuff either) to be living with my parents. I was very motivated to get the hell out, and when I finally did, I never looked back.
D1 is almost 27 and lives with her boyfriend, and it took two Christmases for DH to allow them to stay together at our house. I thought it was beyond stupid to require separate rooms for two adults who live together. My husband was quite the wild one in his youth, so his attitude was infuriatingly hypocritical in my opinion. We finally had a big “discussion” about it , (D1 had said they would respect our feelings but that future visits would involve them staying in a hotel, which I don’t want) and I really stood my ground. I think the first 10 minutes of D1’s next visit was a little awkward for him, but he eventually settled down, and now things seem just fine when they visit.
Here’s what I say. Why so much focus on sleeping together and sex? Do you think that every time they hit a bed young adults have sex? Even if they are sexually active it should not be a big deal to deal with sleeping apart for a couple of nights if it makes things easier on the host - even if they are parents.
It can go both ways. But either way, it’s probably a short time period. Someone - either the young adults or the hosting parents should just step up, discuss any controversy and one side or the other just comfortably settle it.
As parents you are allowed to have your values and beliefs. If you prefer no sleeping without marriage in your house, then young adults should respect that. Again, what’s the big deal for a couple nights? If you go to stay at your young adults house, then you should respect their values and beliefs in their home.
@Marian lol. Is that why the woman send the kids to stay with the dad? lol. I never realized that. I guess I am a bit of a prude. I always figured it was so the Dad can have quality time with his kids. Never figure the mom was making booty calls. I guess your right. It does make sense now.
I don’t think our kids would put us in that situation (?). When they are adults they do what they do, but don’t make it your parents’ business or your parents may have an opinion you don’t like.
Now if my kids were in their 30’s, I might feel differently. Hard to know until we get to that point.
@abasket, even though my response and several others are discussing short visits, the OP actually is asking about adult offspring who live at home after college. So it wouldn’t be a matter of going a few days without sex.
That and the ability to do chores and errands without the kids constantly underfoot. Being a single parent is a strain in many ways.
But I think the dating thing is an important component, especially since many divorced parents do not want their children to meet the people they date unless the relationship has progressed to the point where marriage is likely. There’s too much risk that the SO and the kids may become friends and that the kids may be upset when the SO suddenly disappears out of their lives.
My mom always said that the reason we went to Dad on the weekends was so that he could have quality time with his kids. But she was remarkably upset and even angry when circumstances (such as a long business trip for Dad or a school or Scout event for one of us kids) prevented my sister or me from going to Dad’s house on a particular weekend. Her reaction was much stronger than anything that could be explained by the fact that Dad was being deprived of the opportunity to spend time with his kids. It took me a couple of years to figure out why.
I agree with this for my D that is going away to college and only visiting on breaks and will probably live home for the summer.
I could see myself looking the other way if she were to sleep at her b/f’s house though. His parents don’t mind (they’ve invited her to their beach house - I said no) but once 18, well, as long as she tells me where she’s going… but in my house, no. It would be too awkward.
I think I would feel the same way if she was living at home and commuting. I know my S/O has a problem now if the b/f comes over and even steps foot upstairs for a second, so I doubt he’d be comfortable with it if she lived at home and commuted either.
@Nrdsb4 , thanks for that reminder. You’re right in reading through the posts I totally forgot that the original post referenced a longer stay.
OP, do you have a child who’s considering commuting? I think you have to be clear about what your expectations are and communicate them to your child. What anybody else does isn’t really important. If you’re not comfortable with your kids having overnight guests, just tell them so.
No, my S went away to college and grad school and is now living with his GF. 
The subject didn’t arise when he was in HS.
I was just curious about other people’s experiences, since there are so many discussions of students living at home to save money, especially at this time of year when financial decisions play into final selection.
I expect kids to assume a new kind of independence when they go away to college than when they are living in the family house. It has always been hard for me to imagine how that can happen when there is no “break” after HS.
“When unmarried adults of our own age stay at our house, we give them separate rooms.”
Even if they’ve been a couple for years?? decades???
What about older people ( many older widows/widowers don’t marry again but have long term relationships. My mother and her partner have been together for 25 years).
In my house, we didn’t have separate bedrooms to give to people. Sure, we cold throw someone on the couch but my early bird mom wants that couch to enjoy her coffee and peace before the rest of the household wakes up several hours later.
My 30 year old sister is engaged to a 40-some year old man. Would they have to sleep in separate bedrooms too??
Seems like a good way to discourage visits from “kids” and their SOs.
My parents are in the @IxnayBob and @doschicos camp, which started in HS. Activities with a BF/GF are fine, one night stands are not.
Well, there’s sleep and there’s sex. I’m certainly not having sex swinging from the chandeliers if my parents are in the next room. 
I think it is important to reiterate, as others have, that this question was about a long term period at home during or after college. It is an interesting question, because many young people need to live at home, for a variety of reasons.
One of my kids has s significant mental health diagnosis, and was much safer living at home. When she developed a deeper relationship with a young man, after three months or so, I let him stay in her room. To me, this normalized things for them and made whatever sex they had healthier. The door would be open at times and she would be reading and he would be strumming their guitar. They were sweet.
If I had not allowed this, she would have been living in some unstable (for her) environment. This period at home with limits and boundaries but reasonable freedoms, allowed her to recover. Then she moved out, got a job and pays rent. I am pretty sure that the homey,comfy model of relationship with that young man while at home provided a good model for her to follow.
I had to sell my house after a divorce and now live in a studio. If you have this problem, you are fortunate.
ps I did not have a set schedule!
The median income in the US is ~$50k/year, so most kids aren’t going away to residential colleges. They’re commuting to their local university, attending a community college, or going straight into the workforce. Most probably can’t afford an apartment. I would think that means a great number of kids are transitioning to adulthood in the family home. It doesn’t take a lot of imagination to figure out how that happens. There’s a lot more to transitioning to adulthood than sex, but as far as sex is concerned they either remain celibate or they figure out a way to have sex.
Either way, it isn’t relevant to the financial discussions for college selection. Families who can’t afford residential college aren’t going to suddenly be able to come up with the money just so they aren’t impeding their kid’s sex life. Parents either know about it and permit it, they don’t know about it, or they know but forbid it. The first two have no issues. The third set has to be creative. Young people are very resourceful, so I’m sure they figure something out.
@Marian, long time single mom here. Yep, those weekends at Dad’s are more than stated purpose for sure! :))
@austinmshauri , it IS relevant to the financial discussions for college selection. There are threads right now where people are deciding between several schools, and the affordability of one is dependent on living at home. There are threads like that all the time. I don’t think anyone has suggested this:
If you consider it a subject not worthy of discussion, that’s your privilege. The remedy is obvious.
So far, our kids haven’t brought home any overnight guests to our home. D did have a few HS friends spend the night when we were out of town recently, with our blessing. They have not lived at home since HS, except when they are in HI visiting us.
When our kids were in HS, both had too many medical challenges to have additional energy to spend on cultivating BF/GF relationships.