Feel betrayed

I am a college student. I have a male best friend and we share everything with each other. He is what you would call a playboy. A few months back we got a little intimate...like physically but decided to end it so as to not let it get in the way of us being friends. He is my first kiss. A while back when we were talking on the phone, he told me regretted doing anything with me. We joke around a lot and this sentence kinda surprised me. I didn't say anything because he didn't seem to realise what he had said since we had been pulling each other's leg. Should i confront him or just forget about it and carry on with our friendship? I don't want to lose him as a friend.

We just kissed and fooled around a little bit. I have no qualms over the fact that we chose to remain friends. It's just that he's been with a lot of girls and now for him to tell me that he regrets what we did came to me as a shock. I have not objected over him having flings with other girls so for him to say he regrets what we did, knowing that it was all the first time for me hit me hard. I just can't figure out if I should ask him why he regrets it or just brush off what he said and just not let it get it in the way of us being friends.