Well,
I don't share everything about my therapy with my spouse but I share a lot when I can. I also don't share every single thought I have with him. Yet, we are a closely attached, committed married couple.
The way I understand erotic transference is to understand that it's a normal outgrowth of attachment. And the attachment with our first "love"--our mothers--was erotic also. We wanted to be "one" with her; the way we were in the womb.
So, we want to be "one" with T. But the way to be "one" in this adult relationship would be sexual? Of course, the sexual relationship yearnings are NEVER acted upon.
But it is very healthy to be able to admit and discuss this and explore it with T, and it's okay not to discuss this with a spouse who doesn't understand and who might be hurt by it.
Anyway, this is my understanding.