<human>: Give me a shortened version of the text

Around a year ago, while I was single, I had drunk (but consensual) sex with someone who lived in my college residence. 2 months later, I began dating someone who lived on the same floor as me. He was obviously bothered by my past hook up, which I completely understand, but he didn't bring it up often. We have been together 11 months now and usually have a great relationship. However, in the past four months or so, he has been bringing it up quite a bit. He tells me how he feels shitty about it everyday, how he isn't 100% sure that I wouldn't cheat on him if I were drunk, and tries to make me feel like a horrible person for something I did before he was even a part of my life. I can totally understand feeling bad about it, as I would to, but is it fair of him to try to bring me down because of it? What can I do to stop this?
<bot>: Had a one night stand, began dating SO 2 months later, SO is still upset and trying to make me feel bad about one night stand.