Here's some backstory.

I've been with my boyfriend for 1 year. I'm very 'vanilla' and prudish. My boyfriend is, to be frank, kinky. When we started having sex, he asked if I had anything I would refuse to do during sex. I told him that anal was a huge no go, and thought that was it. I've tried anal once, the guy I was with used a lot of lube, it still hurt and when I told him to stop, he didn't. He knows this. 

Now he's started begging me to have anal sex with him. I've told him that it was a firm no, that there's a lot I might be willing to do during sex, but anal is a boundary I don't want to cross. 

Now he won't stop bothering me about it. We should try this or that, "it doesn't hurt if you use lube", "pleassee", "I promise it won't hurt" and his favourite, "But you've never tried it with me!' I don't care that I've never tried it with you, I don't enjoy it, have a bad history with it and I've tried compromising with you, but you refuse.

He's called me an asshole and asked me why I'm such a prude. I'm seriously considering ending the relationship. So Reddit, who's the asshole?