How are you all staying faithful in an unfulfilled relationship?

I feel like when I was a teenager and almost every guy I start to see as someone to sleep with. Makes me feel like a creep and it is making it very hard to remain devoted to my husband. I suppose the reason I haven't cheated is I'm very reserved in real life.

Edit: I agree with everyone saying that people domt deserve to be cheated on. It's not about revenge