The cruel and aggressive traits and suicidal ideations could also be because of psychological issues rather than psychiatric issues.
He certainly should not stop his meds! It sounds like he hasn't really accepted his mental illness. You SHOULD call his psychiatrist; that's in no way betraying him. I'm sure he could talk to the psych and they could devise a treatment plan that should control his moods, and be less likely to have sexual side effects. Be as supportive as possible; it's a rough illness to deal with, as the "patient" and the spouse!
Good luck.
BP meds in general do not cause impotence but can delay arousal that's all. The worst thing that happens to any man is the existence of a desire but no power to act. However if he is not willing for start then it won't harm him much to decrease the frequency.
Mind you it also depends on his partner !!! i.e. not to let him feel so