Maybe it's the kind of guy you're attracted to-you're attracted to assholes? But any guy, like any girl, can get bored with fucking the same thing day in, day out. It doesn't matter how attractive you are, or how awesome you are because we have tunnel vision when it comes to new pussy. SORRY.
When your boyfriend keeps suggesting to have a 3some, you...might be a redneck. OR you may want to get the fuck out, honestly. yeah.
I've noticed some people-men and women-have a body clock that just "goes off" telling them to end or sabotage their relationship. It's fucked up, man, because it's random as fuck on the inside looking out, but it looks very scripted when you're on the outside looking in. Very plotted, very methodical.
so he demonized you for not allowing a 3some, heheh classic. This dude must be seriously awesome or seriously douchey for you not to see what went on here.
in his mind, you're the one in the wrong = you're evil, and he doesn't give a fuck about risking his relationship.
i dont need to tell you this, or to explain, but it's just fucked up the way this works. Both sides do this.
I'm sorry that dude was a dick, but better to cut your losses now.