College student lodger

I've been married for four years. A few months ago we rented our spare bedroom to a college student
One day when I was feeling a bit down, he was talking about his lack of sex with his girlfriend and I ended up letting me eat me out. He was good at it and made me cum multiple times.
I wasn't going to do it again but it has happened numerous times since. In fact he eats me out three or four times a week and my husband has no idea.
I don't fuck him, blow him or even touch him. I just let him suck on my tits and eat and finger my pussy. He gives me so much pleasure I can't help it.