Infidelity and bipolar

Ah, 10 years ago my husband had a brief 'affair'... I stayed, we worked things out - it took time and help but we got there. Early this year he did it again, I didn't know. Then at Easter he tried to commit suicide and I didn't know. It all came to a head while I was away in June - was asked to come home from my trip as he was unwell. It was only when I got back that it all came out. Into hospital he went with severe depression (the worst I've ever seen him).
He was diagnosed with type 1 bipolar disorder - oh of course I can see it now... The ups and downs, the rollercoaster as I used to call it.
What I would like to know is... Once he is successfully medicated - what are the chances of him being manic again and sleep with someone (or that matter so depressed that he tries to end his life)?

Asking for self preservation really, I don't think I could take that kind of betrayal again, not for a third time.. I'd rather go now so I don't leave myself open to more pain, I'm too old and tired.