Hi! I am glad you came back to us.

I agree with
zachira about having others around you if possible. Another strategy is to pick public places to visit, dinner out, movie, etc so that they are on their best behavior and there can be a time limit built in (ex dinner in a restaurant can only last so long).
How long are they visiting for? Will your wife be with you and can the two of you sort of tag team the conversations and such?
Having your mother put down your sexuality is painful and I would imagine quite frustrating. Can you tell her a simple and calm "knock it off" (in your own words of course) when she says something offensive and inappropriate? There is no reason to sit there while taking insults and doing so only perpetuates the problems. What do you think?
I am an anxious wreck.
Of course you are. She is hurtful, and I read your previous posts where you said you do not like who you become when you are around her, that you shut down after about an hour. That is tough to deal with but it can change with work and time.
I do not know what to expect or how to act. Anybody experience anything similar, or have any suggestions?
Think about this. You know how your parents will act based on years of experience. There will be rude comments and put downs. There may be rages. Expect them and plan accordingly as best you can. Work with us here and we can help with options etc. Change the way you react and instead respond. They will get upset and your father will want to re-stabilize things (as usual).
I just moved this thread here that you might want to read to get a better handle on where your father in particular is coming from:
The Problem with Change See what you think and let me know if it helps you think things through.