Everyone on here has given you great advise.
I don’t think you should confront until you have a plan in action and are ready to move.
Make no mistake you need to take real action.
Shock and awe.
I worry for you. I think you are in very serious danger.
Crazy wife troubled kid. Not good.
You cannot save this marriage. It is over. There are only 2 things you can do. End the marriage and move on or build a new one.
The old marriage and life are over.
The arm over her is very troubling. She is in love with this kids not you. That’s cold even in a sea of terrible stories. It is her and him vs you. She is not your wife nor your friends and I know that’s hard to hear.
She is in a deep love fantasy world. You cannot fight it with logic. You cannot talk her out of it. No words will fix this.
She is in a love story and if you try to stop it you will be the thing standing in her way. It will actually intensify the love story. If you try to stop it you will become the enemy.
If you are standing in the way it might cause the boy to do something drastic as well.
You can’t stand in the way. In fact you need to get out of the way.
But you also can’t enable them any more.
She has to be the one to end the relationship with him not you.
If you confront before you are ready to take action this could get worse. If you think it can’t get worse you are mistaking.
First I want you to kick her out but you may not be able to legally. If you confront early or try to win her back they could just start openly having sex in front of you.
You want to be sitting on the couch and they just get up and go to the bed room. Or start walking in on them making out. That sounds a lot worse to me. It could happen.
Or they could plot and take legal action against you.
Don’t let that happen.
You need a lawyer immediately. Right now. Not some quick phone call where you still want to save the marriage. You are going in to fight for yourself.
Also make sure it’s a real lawyer. Not some guy from your church. An outside lawyer.
Set up an in person appointment. You are going in with the intent to divorce and protect yourself. Not save the marriage.
Ironically, not at first, but in the long term the best way to try and save your marriage is to send her packing to her new life.
When she is faced with consequences and when she is out in the open alone with him reality may set in.
You also need legal advice on kicking him out as with out knowing the law she may try and stop you. Remember she is totally crazy right now.
As for this baby you need the dna test right now. There are many legal implications.
If he is the father he will have rights.
It won’t get easier to find out next year or two years from now.
It is also not fair to the child to let them think you are the father just to find out when their 4 or 5 that your not.
No matter what bond you have they may be able to take her and the child won’t have that bond with you.
That will hurt you even more.
You need to rip the band aid off now and deal with all the pain.
It won’t get easier later.
You need to file for divorce and have her served.
You either need to get custody of this child or get yourself removed from all financial obligations.
You don’t want to be supporting and paying for a child that doesn’t care about you.
That will unbelievably hurt you more and keep you on the hook for supporting them.
My heart breaks for you. I would not wish what’s happening to you on anybody.
But you have to for your long term benefit and healing.
Start separating finances. Open a new bank account and transfer all your money there.
Quit paying for things like phones.
Tell all friends and family.
Tell everyone at the church.
Also you need to move. They have been having sex at your house. It is even the professionals advise to move when sex has occurred in the house.
His stench is all over your house.
Plus if you do reconcile you need a fresh new clean start and a home he has never been to.
And if you divorce you need a fresh start. Not staying in the monument of your broken family.
Just be honest with your kids. You won’t be able to trick the older ones.
As for talking to her there is a poster on here named "BIGGER". If he chimes in listen to his advice.
You can be kind to her through words but not actions.
"I love you but I cannot trust you"
"I want our marriage but I cannot trust you"
You cannot let your guard down.
Go for everything use the fact that the child was underage to get the best deal for yourself.
Only compromise if it affects your other children in harmful ways.
I know you’re hurting. This is so terrible.
There is no way you can be thinking straight right now.
She is in a fog and so are you.
Take decisive action and get them both out of the house.
It will help clear your mind.
It will also clear her mind and give her a dose of reality.
Don’t go easy. If you try to be too kind you will actually enable her to set up a dynamic to get what she wants.
If she comes back begging then post again and that will be a whole round of new advise.
Everybody is pulling for you and I wish you lots of luck.