How on earth did I fall in love with a guy who is BP?

How on earth did I fall in love with a guy who is BP? He's charming, smart and funny. He makes me laugh. We like all the same foods and we have a lot of fun together. He is my best friend. When we met, he instantly fell in love with me and asked me to marry him (which freaked me out and made me very suspicious) I haven't trusted him and Im not sure why, just something in my gut..something I can't put my finger on. This relationship has been a real roller coaster ride. I travel for work which he can not stand. I think/thought it was control and possessiveness. I am always defending myself and dealing with the Spanish Inquisition about everything. He's been rude and isrespectful, emotionally and verbally abusive. Tantrums at times and unwarranted anger and rage. He has said things that can't be unheard. But to top it all off, while I've been traveling, he was unfaithful and of course, I found out, confronted him in the best way I could and he admitted it. Im a forgiving person and I love him but I can't get over this. To top it off, now he said that he feels guilty and can't/won't make love to me. But that's not all, he wants ME to buy a house so we can live happily ever after together. He of course has NO SKIN ($$) in the investment. Just move in with me in a beautiful new home and he will pay "rent"...while I help him get on track with his debt. Oh, and let's get a couple of cute little dogs too.

What??? Wait a minute...? Have I lost my mind?

Please someone tell me how to get away from this guy......How do I gently tell him goodbye? I don't want us to destroy each other. I do love him but I love myself more. I don't want to lose myself in this unhealthy relationship.

Thanks for your comments, greatly appreciate the feedback.

I've got bipolar and i am a male, I'm not very severe however and live and work very successfully. If you care about this man and want to help him first just keep him steady where you two are and slowly get him to a therapist/psychotherapist, a good point of leverage is that he is going through stressful times and it would be good to talk to a professional. There are medications etc. but most of the time the most beneficial cure is support and therapy. If you do not love this man anymore, it's not your fault, just leave, that's life. If you are in contact with his family just give them a heads up just so that they can look out for him. Having bipolar isn't easy but it's not the victims fault, nor is it anyone else's for that matter. If only our modern cultures provided better care for the mentally ill and disturbed, the world would undoubtedly be better off.