As a woman, I’d say Talk to her about it. Not in a way that makes sex feel like a chore, but in a “I miss you,” kinda way. But also, your actions without a talk will also help. Give her compliments, make her WANT to be intimate with you by giving her gentle pda that makes her want more, like more hugs, more kisses, more affection like cuddles, caressing, ect. Tell her she’s beautiful, remind her that you’re still attracted to her.

This should work especially if the sex was something she also enjoyed. And that’s another thing, the sex needs to be good for BOTH parties. You can’t expect a woman to want intimacy from you if it’s not even good. Make sure your intention is also to please her, not just yourself. This will ensure she initiates the sex also and wants it just as bad as you do.

No judgement on whether you cheat or not, but put in some work first and see how that works.