T.R.
I completely disagree with the post saying to never get a divorce. You are absolutely doing your children way more harm than good to stay in a marriage that is grounded in dishonesty and uncertainty. Young children can 100% feel that type of energy in a household. They don't need to understand the specifics of what is going on...they can feel the anger and pain that their parents have toward each other.
Why would you stay with someone and be unhappy when the man of your dreams could be out there waiting for you? Divorces do not have to be messy and hateful. One of my husbands best friends is divorced and has the most beautiful relationship with the ex even though he is now remarried. Even his current wife gets along with the ex. They all realize that their priority is their CHILDREN. The children and reaping all the benefits of this. Of course it is not easy - not much worth having is. But it could be one of the if not the greatest gifts you give your kids.
I would say you know in your heart what your husband is up to. Trust your gut even if you don't have concrete "evidence." Those texts are completely inappropriate and regardless if he has taken his relationship physical, a married man should not be talking (or texting) another woman that way. At the very least, you guys needs some serious counseling.
But I really do think you know in your heart what is happening here...it's just hard to face.