Listen to your head. We as women get so wrapped up in the emotions of the moment that we can't see through it to the facts. I know...easier said than done...and we all want people to love us and no one wants to hurt anyone willfully...but you've gotta think of it this way. You marry him...you're having problems...are you going to go to your best friend (who's also gonna be a witness btw...you should be aware of that by now). You tell her your heart's tale (just like what you did with your bible study conductor.) Do you think you're going to get the hug and tears and hang in there girl! or you're right, he's a bastard! or any of that? You might to your face, but she's obligated to go to the elders and tell them whatever you said if it's off color. Say what?! That's the simple reality of this religion.
You are being emotionally extorted by this man, and if you continue you will allow this religion to do the same. Your BF is a grown man, and if he's SO into this religion, then he should have bluddy well known better than to do what he did with you. This is in NO WAY your fault...this is his. What goes around comes around.
On the flip side, I am sorry that you're having to go through this...but I would rather read this type of thread than the ones of the men and women who stay in for years/decades/etc. in misery and then leave as a broken vessel having to be reglued back together. Chin up girl! This is not the end of the world. :)