Its much harder then that. After everything we went through with my father, my husband felt the same way. When you feel that everything you are has been deeply and purposely offended by someone as close as a family member (and my father and I were incredibly close until he discovered we were poly), then it can be very hard to calm things down afterwards.
After about 4 months of pure abuse from my parents, we were basically told that we were expected to see them for a day or 2 before Christmas. As I was excommunicated due to poly, I am not actually allowed to attend any Christmas celebrations, but we were expected at my parentís home between certain dates, so they could see us before their official celebrations begun.
My husband came with me. He did it only for me and because he knows how important my family is to me despite the fact they have treated us so badly over that 6 month period. We went, and dad was in a foul mood for most of it, but he did manage to calm down and have a long conversation with my husband about the things they usually talked about (they did get along very well before this) and my mum was trying to manage the passive aggression between my father towards my husband and I.
It worked; we got through a whole 2 days together. And although I donít know if they will ever change their opinion, showing up and showing them im not scared of them and also standing up for my beliefs helped *me* get my head around excommunication and being dumped by my family.
You canít change his attitude. Just go, and try and keep the peace. Show him you are happy. He canít tell you how wrong you are and how immoral you are and how unhappy you must be if you keep showing him you are fine.
If you show him youíre not fine, then he will say: no your not sad cause im being an arse, youíre sad due to your filthy immoral life' and that will be that.
Go in with your shields up and show then you are fine and don't let the topic come up. If it does come up, and it gets aggressive, then DO NOT get into a fight. Simply grab your things, thank your step mother for a wonderful meal and walk out.
Repeat until things settle down. He wants to see you more then he wants to hate you, probably. But donít hold onto whatever relationship you had: itís gone, now its time to figure out what your new one will look like.