I caught my new wife screaming with pleasure in bed with my teenage son….what must i do?

I found my son in bed with my wife. She isn’t his mother but I think it’s appalling.I’m 44. My son is 19 and his sister is two years younger. Their mother died ten years ago. The three of us had a tough time.

I was so busy trying to take care of my two little kids and make money as well that I hardly had time to grieve.

My daughter always behaved like an angel but my son was a different story. I know losing his mum hit him hard but I don’t understand why he blamed me.

When the kids got older, I realised how lonely I was and I tried to find love. I’ve had a few girlfriends and my daughter was pleasant to every one of them.

Not so my son. When I’ve introduced him to a girlfriend he could barely be bothered to smile and say hi. Later he’d tell me my girlfriend was ugly or dull. I tried not to get angry as I knew he was missing his mum but it still made me feel really sad.
Then I met a friend of a mate who was lovely and sweet and she made me feel happy inside.

When my son met her he grudgingly told me that she was OK. My daughter liked her, too. I was over the moon.

It was a whirlwind romance and we got married six months later. She made me feel good and she loved my two kids.

I was away at the weekend with work and my daughter was staying with friends. That left my wife and my son in the house.

I came home early and went upstairs to get changed. I found my son and my wife having s_ex in my bed, she was screaming so loud with pleasure and my world crashed down around me, I love them both. I don’t know what to do. I can’t keep up with my son’s bedroom skills

Please help