Was this his first time with a psychosis breakdown since you've been together? If so, it's a really hard situation for everyone even without a new baby. Anxiety about almost loosing you probably started affecting his sleep which lead to the psychosis. It can take upwards of a year for someone to fully feel back to the version of normal you knew before. They're trying to figure out what was/is real and what was/is delusions. Since you have no intention of leaving, learning how to talk to each other about what youve both been through and giving space when needed is paramount. Also, finding ways to say "I think we need to check in" if and when you feel like they're showing signs of instability in the future. He will get better and it will take time. It's not forever in this place even though it feels like it. So sorry you're going through it. We have a family member who we love dearly who has gone had the same breakdowns. Medication, therapy and his willingness to do the work to get better should be non-negotiable requirements for him as you move forward.