My G/f Is Bisexual — Lied to Me About It — & Is Bipolar & Ocd, Won’t Get Help?

She’s lied to me — her b/f of ~ 8 months now — about being bisexual; I know for a fact she is bi. She has a history of cruising bars to pick up men or women for one-night stands. She tells me she wants to have a child with me. She’s untreated bipolar, has a sibling institutionalized for BP (criminal-justice system mental-health facility), has uncontrollable rages and mood swings, hypersexuality / promiscuity, alcoholism (she’s stopped drinking for the time being) and prescription drug abuse (no Rx) (and she has combined booze and pills to the point of nearly killing herself once), and uncontrollable impulses ranging from spending sprees to sudden travel, etc. She’s also OCD, with family history. But she refuses treatment. Only grudgingly has she ‘accepted’ the idea of going in for a full psychiatric evaluation, but without acting on it.

What can I do? I’ve tried being supportive. She’s lied about her bisexuality in what is supposed to be a relationship between heteros. Help!