Cheating is bad mkay. The fact you are asking here shows that you know this to be at best a little murky, and at worst flat out wrong. Someone I am very close with just had their marriage destroyed over the last couple years due to cheating. The relationship was falling apart (which happens), and instead of either trying to fix it, or just get divorced, they didn't do the work and let it fester. Now there is a child outside of the marriage and both of their lives have completely gone to shite. 4 families have been impacted, (the cheater, the cheatee, the one the cheater cheated with, and the spouse of the one the cheater cheated with) not to mention the kids involved who are now growing up without their dad in the home.
No judgements, but there is no way any of this ends well. Cut it off while you're still ahead. There are other women out there. Also, at your age, the divorce's will start to become plentiful. You just have to find them.