Some co dependancy going on here. That and the guy is a full blown user and narcissist as previously stated it comes from being in the cult. A quick read of Stephen Hassan's 'Combating Cult Mind Control' is in order Sunnybear.
Back in the late nineties I had an df'ed jw friend that was my mountain biking / training partner for a summer or two. Very similar in character to your BF : While he was DF'ed he slept around, did all the 'worldly things', used his new found expendable worldly friends for free labour, rides and meals and then quickly cut ties with us once he re-married and was re-instated. Went back for the status and money, inheretance you know, game plan all along.
Although you dated lots Sunnybear sounds like you can do better even if you feel you're getting older and the clock is ticking. It's all up to you really but sometimes better being alone than poorly matched. Anyhow good luck with it all and take care, hope it works out for the better for you. Is kind of a sad situation really, the way narcissists leave hurt and upheaval in their wake... I've seen it up close myself and learnt quite a bit to say the least.