From personal experience, it if pretty effin weird having some else in the same house you shared with the significant other. Esp. having sex with some one new. It feels like cheating and it is an awful feeling.
But perhaps it's just me...
It's not just you. And it's not just in the same house, either. And on occasion, it really... interferes... with the flow of things.
M:23 T:26 Me:53, Wife: 60 S:18 D:16 filed 7/16 W moved out 4/28/17
