Not even on my radar when we met, though he walked me home to my dorm.
I’m not sure when I realized he was “the one” but I think I was impressed that he took me with him to visit his HS friends (not local to his home any more), which he certainly had no reason to do if I wasn’t “the one” for him 
Of course, daily affirmation of him remaining “the one” is more important than first recognizing that he was “the one”.
We hardly ever fight, but have a very passionate attraction and love life after 25 years. The adage about “don’t go to bed angry” is a pretty good idea. I can think of two major fights, in that 25 years, that lasted more than two lines back and forth. Both were resolved partially by writing a letter (on my part). Email makes life easier in that regard, but one has to write with the end goal in mind - stating your case and not beating up on the other person’s position.
As for fighting in front of the kids, at some point if you are fighting a lot, you will fight in front of the kids. My friend who is getting divorced told the kids, together with the spouse, and the kids (pre-K to HS) were pretty much yawning and like “of course you are, you fight a lot and don’t go out together at all”.