Am I the asshole… that doesn’t want anal?

So I have been with my partner now for 9 years and we have a three year old together. He has always been interested in anal sex but I never have. I made the mistake of telling him that I tried it once when I was 18, didn’t like it and then decided to never do it again. I told him this very early on in our relationship so it wasn’t a total surprise. He has always made reference to wanting to do it but I’ve always laughed it off and said not happening. Very recently the subject came up again and I told him that it I didn’t want to do it then but I was pressured, it was a split second experience as it was pain-full and I never wanted to do it again. He has taken this extremely personally and thinks that it’s a slight on him that I have “given” this previous partner something that I am denying him. Apparently have made him fell like “nothing”. The truth is I found it demeaning and didn’t want to repeat the experience. My partner now wants to end the relationship as he doesn’t believe that I was pressured as he thinks that’s just an easy way out and that I am lying. I now feel like the relationship ending is my fault and I should have just done it years ago.