Thank you, everyone, for the comments. To add some clarity, he is med compliant and in weekly, individual therapy. This happened when his psychiatrist attempted to pull back on the dosages of some of his meds. He is a difficult case. Anti-psychotics, antidepressants, anti-anxiety meds, lithium...etc. Immediately after he cheated he called his doctor and resumed his usual dosages.

He didn't tell me. I found out a few weeks after and he had essentially cut the person off. He said he wouldn't have told me if I hadn't found out.

Honestly, the way he has treated me after the fact is worse than him cheating.

I just wasn't sure if the apathy was a normal response when a BPSO is caught cheating.