My best friend is a male and we've spent a few years becoming really close by now, but at the start of the year we tried to turn it romantic for a couple weeks (big mistake) before I realized it wasn't really going to work out for various reasons. He blames me for this which is understandable and I felt guilty as he still liked me after that, so I wanted to give him space, but he didn't want to stop talking. Then around a month after I started to have interest in another man, and this obviously upset him as again he still likes me.
We got into multiple huge arguments over this over the course of a few months, but I cannot help how I feel. During these arguments he would threaten to leak private/sensitive information about me to my exes and his friends, and would say something like he would try to ruin the man's life if he found out who it was. I also feared he would spread rumors or leak chats, etc. He said he didn't particularly want to hurt me, but felt like he had to do these things because he didn't know what to do with his anger and upset-ness about the situation.
He didn't end up doing any of this and later he said he didn't really mean these things/would never do them, but it is still scary to think that he could because I have entrusted him so much personal information about me provided that we are best friends and extremely close. Again, I suggested that we stop talking multiple times because this was going to routinely become an issue in our friendship and it did repeatedly. I believe if he still liked me that we would never be able to be proper friends since it would be adulterated by his romantic feelings. I then I said I would be taking a break from communicating with people for a while and I then stopped talking to him for about a month.
I got back into contact with him after that month as I felt bad for leaving it that long and we began talking again as friends, but during the time I was gone I gained a boyfriend and am terrified to tell him because I worry he is going to lash out at me and threaten to do something bad to me or to my partner. I also don't want to upset him with this information as I do care about his feelings and I still am regretful that I could not make it work romantically with him as he wanted. I did mention to him I felt I would end up dating the guy I liked previously before we stopped talking so I don't think that that information was fully withheld before, but it still makes him very upset. It has been about a month since we started talking again and I still have not brought this up which may be my mistake.
He is a really nice man otherwise and a very good, caring friend which makes knowing what to do in this situation very hard. He sometimes says that even if these things upset him that he would never want to stop talking to me because he loves me more than any of these circumstances, yet I don't think he will ever stop loving/liking me and it makes the friendship feel like I am constantly stepping on eggshells. It gives me anxiety whenever he begins to get upset about any choice I make that isn't in line with his wishes of being my object of affections. I do feel that it's best we cease talking, but every time I bring it up he is extremely against it I think because he doesn't want to 'lose me'. He had agreed to mutually cut contact once before but he returned two weeks later to talk to me again.
I don't like the idea of losing an extremely close and important friend but I don't see how this could get better. I also get very anxious about what he may do with the sensitive information he has on me if I were to suddenly just cut contact. I am extremely lost and have no idea what to do, everything I could do makes me feel very guilty and bad. Any thoughts are appreciated