I do this very same thing and I am married. It's like my brain takes over my body and all I can think about is having sex with random people, I even dream about it when it's really bad. So usually the first opportunity I have sex with whoever is willing and usually afterwards I hate myself for it. I almost lost my husband over this, but I can't make him understand that it's an impulse that I usually can't control.

The only advice I can give you is to try masturbating to help lesson the desires, if you don't have any sex toys, get some. You definitely don't want to be the person responsible for a break-up in a marriage.

I hope this helps, sometimes it helps me.