I don't want to do that!
Well why should you?
Just because you prefer the male to the female form, it doesn't follow that you have to indulge in anal sex. Truly.
Love is about doing what you each want, and doing it together. It isn't about one of you doing something that the other wants and not enjoying it. It just isn't.
If you don't want to become anally involved, that is just fine. There's plenty of fun to be had with oral sex, and with mutual masturbation. There is nothing wrong with not wanting to do something.
The only "wrong" thing would be if you didn't tell your lover.
And do remember, sometimes you might just not feel like it. And that's OK too.
Being not classically heterosexual doesn't mean you have to fuck like rabbits every chance you get. It just means that you have different sexual desires from the purely heterosexual folk.
Well I know it's obvious, but feeling under pressure is the last thing you need.