If she is serious then it sounds like it is time to get a new phone with a new number! That will stop all " blocked " numbers, and give a fresh start. She can also let him know if it persists she'll get in touch with his wife. Of course this will be done in front of you...
Excellent suggestion up there ^^^^
Also, as LFW mentioned...be prepared for some backsliding on her part.
In all of this...keep being the MAN you want to be! Keep the changes going that YOU feel need to change.
Peace, Eric
"The difficulties of Life are intended to make us BETTER,not bitter". "Fear is a prison, where you are the jailer. FREE YOURSELF!" "Life is usually all about how you handle Plan B." - Jack3Beans