Slut tamer

A guy or girl who successfully dates (exclusively) a former slut and that slut is now faithful to the guy or girl.

There’s two scenarios for a someone dating a former slut
1. The slut continues to sleep around and is cheating their partner
2. The slut actually is exclusive and the person they are dating is a slut tamer

“I’m in a relationship now! Exclusive!”
“...but you’re a slut...”
“Guess he’s a slut tamer”
“Oh right on! Good for him!”