Experience with autistic partner?

He doesn’t have a formal diagnosis, probably because this kind of thing is normally done during childhood, but I’m 95% sure my fiancé is autistic.

Right now his diagnoses are ADHD and mixed mania (bipolar). He does a bit better on bipolar medication but even then there’s still signs. He doesn’t understand social cues or norms. Can’t follow a conversation except with me. Really sensitive to criticism and just kinda selfish in general. He has a bad temper that’s gotten better, but is still prone to angry episodes when things don’t go his way or he can’t do what he wants.

I love him so much and we have a family, an infant son and a baby on the way. He loves them and me and I know he does his best but it’s so exhausting. I have anxiety and severe depression myself, and it’s like I have to mother him because I can’t trust him to do things right. I have to make his phone calls because he can’t communicate right over the phone. I can’t leave him with the baby for more than a few hours because he just doesn’t seem to grasp how to care for him even though he tries. No way could I leave him with a toddler and a newborn.

Does anyone have any experience with this and could share? I’m just really tired and it sucks because I know none of this is his fault, but it still leaves me with the extra stress. Sometimes I think about how it would be easier to just leave, but he really is a good partner and dad and he does his best. I could easily find a partner without autism who I wouldn’t have to stress so much over, but they wouldn’t be him and I really just need support.