Okay, if the sex is still super hot then there are undercurrents in the situation that are not being addressed and could even serve to stabilize or even recover the relationship. You're leaving out a big part of the story whether you realize it or not.

You are not repulsed by your wife's infidelity; you're powerfully aroused by it. Did you have or share fantasies about this in the past? Is there a chance that you steered her into her affairs by wordlessly sharing this impulse? Could you acknowledge and harness the impulse to recover the relationship for the sake of your child?

I don't judge you. I hope that you and your wife can achieve an equilibrium that will benefit everyone.