Whose is the primary account holder on her phone?
If you are, get a detailed transcript from the phone company.
If you are not, you need evidence another way.
You need that.
Beware of her creating a situation inciting domestic violence, whether it be verbal or physical abuse. Be ready to walk away from her, taking the kids with you, with evidence of her adulltery already in your lawyer's hands. Make sure you have your own copies.
Look, if you did this to her under your current circumstances, she would likely screw you royaly in the family court system. It's bullshit to give your spouse a pass just because she's a woman. Get your evidence, get it to the BEST lawyer, and be ready to file with one day's notice.
Be ready to file and kick her out of the house.
Set the standard for devotion to your family by not tolerating members who would weaken it.
Adults and children, dedicated to their family.
it is precious.
Tough love.
Her friend is a piece of s***, and a bad influence.
If you want to be bold and take a chance, confront all three of them together in the manager's office at the gym. Do it calmly, firmly, and look each one in the eye. File for legal separation THAT DAY with the children in your custody.
Can't stand up for yourself?
Be prepared to be screwed over emotionally and financially.