Seriously it's the enforcement that will make a difference here. You can tell her till her face turns blue but she will continue to see this guys. Oh and the whole phone privacy thing.... That's cheating sign #1.
Not evidence or proof, but sign. She does not respect you or your boundaries so you should pull the plug. Otherwise she will continue to do this.
I know the kids issue is the hardest, but your daughter is learning how to treat her future husband from her mother, and your son at this rate will grow up thinking that a relationship like the one you have is to be expected. Besides can either of you really endure 14+ more years of this?
