How do I create a new attitudes towards a partner who is more sexual?

C: We are separated but we are in touch to see if we can salvage things. He is open to sexual encounters. Yesterday, he communicated his sexual desires with someone else (a couple) and acted on them. If there is a future together, he wants that continued freedom.

I am here:

T: He always wanted this and pretended he could be happy with vanilla me – but it was always going to go this way.
F: Inadequacy
A: For once, I am feeling it all.
R: I am challenging my “life manual” but my T and F cause pain.

I want to be here:

T: This could be a healthy compromise when my sex drive is low.
F: At peace
A: I share the experience. I embrace the experience.
R: Movement towards empathy and no judgment.