I hear you there. The crazy, and yet not surprising part is that almost every single gay man I know who is in a partnership or even married to another man in a supposedly stable and monogamous marraige, either is cheating on his partner/husband or being cheated on. I know this because sometimes the husband who I was not as close with, would approach me in secret or email or contact me via texting, and want me to help them lie and cheat on their partner or husband. They also wanted to do extremely dangerous things like have unprotected anal sex, and I live in an area and country where HIV, Hep C, and everything else is extremely common.
These people do not have open relationships or marriages, or arrangements where one or both people are allowed to ocassionally have sex with someone else together or separate from their partner or spouse.
I am not a homewrecker, or a snitch. So I do not take them up on their offers and I basically tell them off or do not talk to them unless I see their partner or husband who I am platonic friends with.
I told this to an older gay friend and he said how all of this with the lying, cheating, pretending to have the perfect marriage while cheating, etc. Is extremely common among gay men.