bipolar boyfriend is having a freak out, anybody have advice?

Okay, so I'm 20 and have been off and on dating a bipolar 24 yr old for 3 yrs. He can be the most amazing loving man, and honestly I don't think I'm capable of loving anyone as much as I love him. We've been solidily together now for 5 and a half months without break ups and things have been great..and no he isn't on meds.. But anyway someone made a rumor up about him in his church, it was one of his friends. A few of his other friends who supported him also started gossiping about him behind his back and now the its fueled the fire so much he couldn't take it. He left the church he's dedicated his life too. Now he's been going to church with me, things have been great. We've been looking at engagement rings and he's already decided how he's proposing to me..something ridiculously flamboyant and expensive..but anyway. Last week he got a phone call from someone in the church saying the rumor got back to the head people, and some of the people he trusted screwed him over. He's been off ever since. He wouldn't talk to me all last week, told me he wanted to be alone, so I left him be and sent him words of encouragent. He came down this weekend and acted really sad and depressed with all of our friends. The next night we sat in the car and he said he's sorry he's been acting so distant, he knows it isn't right, but that he really doesn't feel like he can trust anyone anymore..and though I've never done anything to break his trust he just can't trust me or anyone else. When I tried to comfort him his whole body got rigid and he wouldn't turn his head towards me..when he finally did he was trying to not cry. I told him he never lets people in and he needs to let me in, I asked him if he knew how much i loved him. He said yes, but he doesn't deserve it. He said his rep is ruined and if I'm with him mine will be too..he doesn't want to hurt me that way. I deserve better. Then He says he's far away from god right now and all he's been hearing all week is god saying leave her and come back to me.. but that he doesn't want to leave because he loves me and he's resisting..so I asked him if he's sure its god and he said no. He said he didn't think if we broke up it would be forever just long enough to get his life on track and get closer to god. I asked him how this would be accomplished since he only goes to church with me because he won't go to his own. He didn't know, told me not to cry and that he loved me..he said he's not leaving yet, he doesnt want too. He called me yesterday, sounded a little happier, a lot more pep and he was sweet. I was talked to him about how 2 weeks ago he was ready to marry me and propose, he asked me who said that thought ever left his mind? and told me which day he was planning to come down and spend with me this weekend..I'm confused..one cuz I can't tell if this whole break up thing is his bipolar disorder kicking in and telling him to run cuz i'm the closest thing to him and i'll hurt him. two. whether its god or not..i don't think god would do that to me, since he brought us together.and 3. how do i stop him from running?