The title is a bit misleading, since we're (best) friends first and lovers second, but I wanted to give as much information as possible. Before Tom met me, he was really close friends with a girl named Mary. Mary had obvious feelings for him, and at the time he thought he might also feel the same way about her, but then quickly decided that there was too many incompatibilities between them and sat her down to go over every reason why he didn't want to date her.

They stopped talking for a while and we got closer, but then Mary contacted him out of the blue and they started hanging out/being friends again. I didn't think anything of it until Mary started telling our friends and acquaintances that she and Tom were dating. Tom told me flat-out that it wasn't true, but he thought it was a funny joke to play on our friends since he and Mary were so close (???). I told him that she obviously still has feelings for him and he told me "Yet I reject all of her advances, and spend all of my time with another girl (me)". Mary still obviously has feelings for him, Tom has told me several times that he isn't interested and this whole situation makes me uncomfortable, especially since our other friends didn't know.

So I decided that our friends had the right to know that the relationship wasn't real and told most of them, which seemed to upset Tom because he said I was "ruining" his fun. Since then I've not done anything sexual with him, keep our conversations short, and hang out with him much less frequently, but Mary has also been somewhat hostile with me and has accused me of being "jealous of their friendship" and "punishing Tom by spending less time with him".

AITA for telling our friends about this and distancing myself from him?