<human>: Condense the text into a few key points

Dear Reddit,

This is obviously a throw-away, and with good reason.  If I go to the extreme in terms of protecting information, I apologize. Here is the situation:

I recently (last night) came into information about a family member of mine. They are a family member through marriage. The person in question is married and has a child/children.

The information I stumbled onto about this person is that, despite being married, they are trolling for sexual encounters on Craigslist.  Both genders. Giving and receiving.  It appears that it has been going on for a few weeks now.

I don't know what to do with this information, but there are a lot of facotrs at play.

1 - What they're doing could have horrible consequences - their family being torn apart, the bringing home of some disease, who knows what else.
2 - They have a kid/kids at home, who I am very close to. I couldn't stand to see their heart broken when Mommy/Daddy is kicked out of the house and not allowed around anymore.
3 - The person's spouse is a family member who I am very close to.  I have trouble believing in God, but I am certain that this person is a saint. The thought of this going on behind their back makes my heart ache.

I don't know what to do.  Pretend I didn't see anything? Confront the offender? Notify the victim? Get another family member involved? I feel like I have just entered one of the most important ethical crises of my life, and I am at a total loss for what to do next.

Please help!
<bot>: Discovered that married family member is trolling for all kinds of sex on CL, thier spouse is unaware. Don't know what to do.