Having trouble functioning is normal, alas. Finding out that you've been betrayed is traumatic.
Exercise is great, but if you want to cry, crying is great, too. When you're done crying, though, get your body moving and hydrated. You know that, right?
Have you counseled victims of infidelity. If you have, what have you said to your clients? Have those words helped them? Do they help you?
I was very strong emotionally on d-day. I hope and expect that as a counselor, you were in oretty good shape emotionally before Monday. My strength helped me, and I hope your strength heps you - but being betrayed is a tremendous blow, extremely disorienting. What I found helpful was activating an 'observer' ego state that just watched me ride the waves of pain and made sure I met my commitments in between the waves of pain.
Three days is a little quick to get over being betrayed. Think 2-5 years for recovery. If your H isn't ready for the long haul, I don't see how he can change from cheater to good partner.
Have you asked your H about the other CC charges? IDK ... 'Asian massage parlor' doesn't say 'massage therapy' to me. If I needed massage therapy, I'd go to a certified massage therapist. So I wonder if this was his only 'happy ending'.
*****
Your H doesn't look like a good candidate for R to me. But that's for right now - he may change.
What you need to be telling yourself are messages like:
This is about him and his issues, not about you or your M.
You can heal whether you D or R.
Your kids can heal even if you D - in fact, if your H won't make himself into a good partner, they may heal more fully if you D than if you stay together.
He has to heal himself - you can not heal him. You can provide emotional support, but he has to heal himself, just as you have to heal yourself.
Have faith in yourself to heal.