This is H exactly and we have talked about this. He has acquiesced his whole life and wound up here.
Try the truth:
Thanks for thinking about me, but I am not comfortable with that. or I have plans or No, thank you. etc.
You get the drift.
I totally get that and I was honest when I said no the first two or three times. At some point I get wore down and I either get angry or just give in with resentment. I need to learn to be firmer in my no or be happy with my yes.
You can not change your past, but you can ruin a perfectly good present by worrying about the future.