Dekh bro, guys are wired to seek out partners, marriage as a concept is new to humans.
Plus other women find married/committed guys more attractive because they're outside reach and already selected by a woman.
This is why extra marital affairs happen and are more common than you'd think. Some couples give each other passes or have contracts with each other to manage this in a way that works for both.
Very few people live out their lives completely monogamous without ever cheating on someone. It takes effort to find the right partner and build a relationship that's fulfilling for both.
If you try to deny your biology you're going to have a hard time trying to moralise it all. I struggled with the same for a while. It's upto you to decide how you want to conduct your marriage/ relationship, there are mostly no right or wrong answers that apply to everyone.