My S.O. used to be jealous of my T. I started therapy and started seeing a Pdoc again 2 years ago. He thought the the meds would change who I am and the T would tell me to leave him (he was very controling and verbally abusive). He thought that me talking to a T would be me keeping aecrets from him or speaking badly about him behind his back. He was also jealous that I had someone to talk to and he didn't. When I became really attached to my T he was afraid that I loved her and trusted her more than him (I did). And it would upset him when I would come home upset from therapy because he didn't understand how that could be helpful.

But it's been two years now, and he has since come around. He now encourages me to go to therapy. He even pays for my therapy now! I think what made the difference was being transparent with him. I always tell him what happens in my sessions. He likes it because he learns from it, and he feels a part of that area of my life even though he's not present. He has seen how therapy has helped me, which in return has helped him not have to worry about me as much. He also knows that I have the ability to love him and another person at the same time.

I don't know if that helps you any or if it could even apply to you. But transparency is what helped in my relationship.