I guess I wound't make a big production out of it.

"W, I know you're texting with OM and that makes me feel disrespected and hurt. If you continue to text with OM, I'm forced to stop paying for your phone. I can't fund this behavior."

Something simple..

M34 W35
S5 S2
T10 M6
on/off over the years including her A
Recently-
Nov 2015 bomb
Nov 2015-Feb 2016 Reconciling
Feb bomb
March-April Reconciling
May - bomb
Mid-May I tell her I'm done