when we are depressed with see it through dark lenses we are so happy to be alone we crave it. we don't enjoy things anymore especially sex...even though it shapped through my relationship with a guy I know as my "Booty Call" it was fun at the start but soon as it went dark in my mind I didn't want to have it anymore. I stopped answering his calls and his texts it was like everything felt better for the time.

If you can keep having him make a joke so you can laugh all will be saved i am sure...
Its all about the happiness around him the way you feel when your in his arms his cuddling you in bed. At first it might think your alone and it doesn't feel good but push those feelings out for the small time its wonder lust. hug him each and every day or ask for a hug its the simple things you can make you feel a bit better.

I don't know if you can fix mental illness but I guess you certainly try.