Call him out on it... I front of roommate...

Something tells me he would play dumb and act as if OP is just "jealous and trying to tear their relationship apart". I've seen being honest/confronting this type of situation backfire in real life, movies, and books.

Oh yeah that's a smart idea

it won't work, he will deny it

I reckon it might be a ploy to drive a wedge between the room-mates. Maybe so she will move out and move in with him, or something. I would tread very carefully on this one, but don't let him in again unless your roommate is present.

Be sure to LOUDLY explain the situation to the both of them. :)

I hope your roommate dumped that bastard.

Next time he does it record it

Kudos for kicking him out, I hope your roommate loses him asap... sorry to hear you got dragged into such an unfortunate situation, OP

Tell your roommate, and if she doesn't believe you, it'll only be her problem for not listening.

Oh yeah cuz in no way would this make OP's life with her roommate horrible if she just said that that happened especially when the boyfriend is playing ignorant

well.... now it's the waiting game. wait for him to try again then discreetly turn on some form of camera. Then show to your roommate.

There is no way to win in this situation. Even if your roommate is a reasonable person, she'll be more likely to believe her bf over you. Even if you offer recorded evidence, she'll likely get angry at you and her bf will say that you came onto him in the first place (before the recording took place). I know you did nothing wrong, but having been in a similar situation, I know how unexpectedly these things can play out. Good luck op!

My advice would be to avoid him like the plague!

I accidentally clicked YDI, but then I realized it said ROOMATE'S boyfriend. FYL.

You mean you purposefully clicked YDI then realized you misread the FML.