Serenity, I wanted to give you a hug, because you probably need one . Yes this situation SUCKS a lot. You sounds like your doing well all things considered so I do think you'll decide on the best answer for you as far as the future of the relationship goes. Something none of us can decide for you anyways. That being said, a few words of wisdom from "being there"
1) Give yourself time. To process, to feel what you feel, to be gentle on yourself, to make major decisions, to grieve the loss of the honest relationship you thought you were in
2) Keep yourself healthy. Watch your eating and sleeping and make sure you get enough of both. If your moods deteriorate too much, talk to a counselor
3) Counselling (individual, couples, both) can be a huge help
4) It does get better

• in time
  if he's honest
  if he answers your questions
  if he's supportive

I agree that he can't fix the problem for you, he has to do it for him. But if he's willing to go, I wouldn't suggest otherwise. At some point he'll probably be asked why he's there, if he says "because my gf doesn't like what I did and told me to come", the counselor will probably set him straight, he'll learn that he needs to do it for him.

"I know that my bfs behavior is not a reflection on me, I have done nothing to deserve this."

I'm really happy you feel this way, and I hope as a psych major you can avoid falling into that trap. But it is all his responsibility to own.

Cheating is cheating, yes there are different "flavours" but they ALL suck. Your emotions all sound very normal considering the situation, hold on tight because they can roller coaster back and forth.

The only other thing I'll comment on, is because this sort of thing has happened before, and because it's always you finding out, never him confessing, trust will inevitably be difficult. I don't think it would be unreasonable for you to ask for the passwords to the accounts he was using for these activities. Verifying that he's telling the truth will help him earn trust and make you feel more safe.

If you ever have questions, want to hear more of my psychobable or just want to vent, feel free to pm me