Ok, back to role of the real OP. (If you are getting laid by your spouse who is off with someone else, then yes, you would qualify.)

Roles of OP:
* To piss off spouse. Perhaps to get back at or to hope spouse will dump them upon learning the news, i.e. the coward's way out.
* WAS has been looking all along and finally found a suitable person (for whatever reason)
* Happens to be there when someone feels they get no emotional support from their spouse

Just some thought.