I started reading your post thinking “You know, I text my female best friend quite a bit myself..” then I read your last paragraph and you said he tells this man intimate details of your relationship- arguments, sex and right there is the biggest of red flags. That is betrayal of your trust and disrespect for the privacy and intimacy you share. He is way out of line.

Then I read the other posts about your husband’s sexuality- that is very difficult and it does indicate their friendship could be something more.

I’m wondering why you’re doubting your instincts? I guess you will have reasons for that but from an outsiders point of view it seems like you’ve been putting up with a lot of stuff that’s hurting you.