Facing divorce of schizoaffective bipolar spouse?

My husband has schizoaffective bipolar disorder. When we first got together, i was unaware of the "schizoaffective" part of his diagnosis. I was under the impression for years that he was simply "bipolar". Our relationship as been an insane struggle from start to finish and its finally reached the point of no return for me. We recently separated, we have a 2 year old daughter together and I have a 5 year old son from a previous relationship. I met with a lawyer last week and informed him of the situation, my husbands mental illness and some of his erratic behavior as of lately. When my husband and I discuss divorce, we've talked about agreeing on 50/50 joint custody and visitation. Cut and dry, sign the papers and be done with it. However, there have been a couple incidents since the separation where he has threatened my life, told my son he hates me while i was within ear shot, refused to give the kids back to me over a utility bill and his anger and mood swings are out of control, but he does have moments where he seems normal, logical, rational and calm. This is just to name a few things I've experienced with him, the list could go on for days.

My lawyer advised me to file for sole custody of our daughter because of his mental illness. He said if my husband was awarded joint custody and went manic (as he has in the past three times, all involved hospitalization) then I would have no control or protection of my daughter in the event of episode and that it would be difficult to undo a ruling and convince a judge that I should be awarded immediate sole custody of her in the event that he falls ill again with his disorder.

However, filing for sole custody would involve me having to expose all his medical records that would show how he was declared severely mentally ill, on SSI disability, hospitalized with psychosis 3 times and previously petitioned to go before the board of mental health, was psychologically evaluated and court ordered to receive treatment and therapy.

My lawyer said the process would include another petition for him to go before the board of mental health for another psych eval, he'd have to take a 4 hour parenting class and be deemed fit or unfit to have visitation with the kids. In which case, a social worker would most likely have to surprise his visitation with them until a judge ruled otherwise.

I'm conflicted because I do believe it is in my daughters best interest for me to have sole custody in the event that her father were to fall ill again and not be of sound mind. But I do not believe him to be unfit to have visitation and the thought of supervised visits breaks my heart, because I dont feel like he deserves that. I do think he needs to seek treatment and get on medication but I cant trust him to take care of that on his own. He is a ticking time bomb and one part of me worries about him going on while he has the kids, and the other part of me says my kids are fine in his care.

I'm paralyzed with what decision to make. I dont want things to get really ugly and nasty. He will never understand that my decision to file for sole custody is strictly to protect my daughter in case he gets ill any time in the future. I'm paralyzed because I dont like the idea of him not getting to see his kids during the process or how he might react when he gets served with papers as he will not be expected to see any order for sole custody.

I would appreciate any feedback, knowledge, advise or insight. Thank you.