I think we all understand the dynamics of masturbation just fine.
The issue arises from its use as a substitute when the other spouse is more than willing to provide sex - likely in just about any form at this point.
What her husband is doing is disrespectful to FF, regardless of his claims or reasons.
His actions are most certainly selfish.
-NOPkins-
I will ferret out an affair at any opportunity.
-An affair is the embodiment of entitlement, fueled by resentment and lack of respect. -An infidel will remain unreachable so long as their sense of entitlement exceeds their ability to reason.