Yeah, my therapist also sucks at emails. In the beginning I didn't realize this and we wound up having a problem because he didn't reply to a scheduling email. Now that I've realized how much he sucks at it, I still feel totally free to use email but I just don't expect a reply. I think he's a great therapist, so I've just adapted to this flaw. But he is very responsive with phone calls- if I need to talk to him, he rings me back every time.

But maybe there are more problems with this setup than just emails? It sounds like you see him infrequently - is he very busy? Would you prefer to see someone with more availability? It sounds like you would find someone more consistent a lot less stressful.