@rebeccar I am sad that your fiancé caved to his parents so quickly. Very glad you picked the venue that you wanted, and not the venue his parents wanted.
You mentioned not wanting to lose the wedding of your dreams. But do you really think that this is the end of his parents meddling? They will continue to suck the life out of your dream wedding every chance they get. The band you pick, the flowers you choose, the color scheme, number in bridal party, they will all be awful choices and will be heckled throughout his side of the family. And they will be as vocal as they can with you, too, so at least limit your contact with them.
Your vision of a lovely wedding day focused on you and your groom is not going to happen. You will be holding your breath and waiting for them to behave either passive aggressive or outright shockingly as they both put down your choices and at the same time pretend to your guests that they are the hosts.
Will you plan to allow them to give a speech, or even a toast? And if not, what will you do if they commandeer a microphone on their own?
I highly urge you to wait for payment from his parents before issuing invitations to anyone on his side of the family. Have fiancé ask for payment now.
Have you been to counseling with your fiancé? You need a third party to talk through how fiancé is going to stand up to parents and protect his wife. You need to agree ahead of time on things like how you will divide up your vacation time between families, where will you spend major holidays, and how will you hande individual “demands” that you simply must be in attendance for Uncle Bob’s birthday party.
The fact that his parents feel so free to disparage you should be a red flag to you. If you are not in counseling getting your fiancé strengthened to do the hard work of breaking away from his family and joining you in solidarity against them, there is not much hope for your future life together.
If your fiancé doesn’t embrace the tools and methods of the counselor, you will end up with a spouse who tries to agree with you on how to handle his parents but will, instead, cave to his parents and disappoint you.
It is natural to be influenced by the parents who raised you. To go against your parents’ wishes takes great strength of character. And the challenges will continue throughout your marriage, so the foundation between you and your fiancé must be deep to survive. Because your in laws will switch to driving a wedge between the two of you. They will be clever, and will use subtle tactics that build over time. Comments made to you out of earshot of your spouse will be denied, setting your spouse up for a power struggle on who to believe.
What if his parents insist you must include a particular person as a bridesmaid or groomsman? What if they insist on adding something to the ceremony (not familiar with Jewish/Persian culture) that you and fiancé have decided against? So many opportunities to push their agenda. Worst case scenario is that your parents and your fiancé shell out major bucks for an event that does not meet your wedding dream expectations. Disappointment is highly likely no matter what you do.
To recap, get fiancé to ask for their money payment now. Find a counselor and set up a series of appointments (one session is not enough) and lower your expectations for your special day. With your inlaws in the picture, you should expect some passive aggressive behavior, and some unkind remarks. Only you can choose to ignore them and focus on your fiancé in your wedding day.