Santa clause is not real. That does not mean we should tell children the truth. We let them believe the fairy tail as long as possible. At some point someone tells the child that mommy is santa. Now the child is confused. Time for the child to seek the truth.
Same thing with wedding vows. We let the couple believe this. Some may live the fantasy. Most will not. You lived the fantasy. ILYBNILWY does not line up with the fantasy. Now you are confused. Time to seek the truth. Most likely your wife has feelings for another man.
OZ"So what do I do????"
R2C highly recommends doing nothing right now but reading, understanding and making a plan.
PuppyDogTails, AllenA, Gucci, RobX, Steve85, AS, Sandi2, Coach are very wise and you should listen and understand as much from these people as possible. There will be conflicting advise. That is OK. Best to understand as many of your options as possible, and the likely outcomes.
If I could, I would take over your body and DB your wife back. It would be easy for me, I am not emotionally attached to her. Woman are easy to seduce.
"What is best for my kids is best for me" Amor Fati Link to quotes: https://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2879712