I hear your pain.
I would also like to say that I am not married.
For your benefit, I would return to therapy. You know this isn't going to get better without it.
I beleive eventually you should tell your wife why you are going. But if you don't want to say so in the beginning, you can tell her you need a "tune up" from the issues you previously addressed in therapy.
Obviously, it would be best if you could be forthright with her from the beginning. But you should not deny yourself the care you need just because she is reluctant.
Acceptance on someone else's terms is worse than rejection.