I have to deal constantly with men giving my woman attention. Steve will have to as well. We all do.
Where is the line for tolerance? Where is the line for action? Where is the line for consequences? Where is the line for ending the relationship?
The lines are different for all of us. The lines help protect us. They are our boundaries.
His wife has a need to sing. Steve should go enjoy her singing. His wife also has a need for attention. It is his job as the husband to meet this need, otherwise some other guy will.
As far as the deception, Steve needs to address this in MC. I would make MC as part of the consequences.
"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