Your WW has to go NC with this OM. They can not work togehter.

You need to set down some conditions for recovering your marriage. These include NC w/ OM, getting a new job away from OM, no hanging out with other men without out, transparency and accounting for her time, marriage counseling, 15 hours of time/week together, etc. If she does not agree to these conditions immediately, you expose to her family, her friends, your kids, the hospital, OM's family and friends, etc. You then let exposure do it's work.

At the same time, you need to start getting ready for plan B/D. You need to document your time with the children and your WW's late nights. You are actually in a VERY GOOD position for custody. Your WW feels completely entitled to do as she pleases. Maybe the prospect of getting forced out of her home, losing custody of her children, and paying child support will knock her entitlement down a notch or two. I would try and plan A for about 2 months after exposure, and then quickly transition to a plan B/legal separation or divorce. Your WW is SO entitled right now, it will take some drastic measures to get her to change.

Fish, what I would do if I were you is get better evidence and then expose her affair. For example, you could put a VAR in her car and put flexispy on her phone. When you say you have text messages, what do you mean? Do you have the actual texts?

I don't understand why it took you 3 years to get this far, but it shouldn't take you longer than a week to get some real evidence.

Once you get the evidence, you should expose at the workplace and to friends and family members.

If she will not quit her job then you should go to Plan B.

My suggestion would be to take a more pro-active, strategic approach. You may decide to divorce in the end, but you still need to get the goods and expose the affair.

Also, have you even DEMANDED that she quit her job? Have you even asked? Most men are too scared to even ASK.

In all seriousness, you have done one of the worst Plan A's I've ever read.

You did plan CA for 3 years. ( conflict avoider )

No exposure?

Your children are now older teenager.
Expose to them first.

"Kids, it pains me greatly to tell you this. Your Mother has broken her marriage vows and has been dating OM ( or maybe OMs ) for 3 years that I know of. Perhaps longer.
I want you to know that our marriage is in serious jeopardy. Whatever happens, none of it is your fault or your responsibility."