What are tour experiences with a bipolar 2 spouse

I am pretty sure my fiance (or ex now because he dumped me.....I'm 20 weeks pregnant) is bipolar.

He got diagnosed as bipolar 2 years ago by this quack of a "doctor." I say that because I've seen this guy myself once, before I met my...ex (weird calling him that).

Anyways, I'm seeing a trend happening, and I don't know if maybe that doctor, as quacky as he is, may be onto something, or it's something else.

He's currently taking remeron and has been for almost 3 weeks. From what I can tell....they're not working. I've barely seen or spoken to him in a month and a half.

I'm desperate for insight. We are having a baby girl in Sept. I have 3 other kids, 2 of whom call him daddy and are heartbroken. I just am trying to figure out if it's worth saving or if I should just cut my losses.