Please forgive me for being a big poop-head downer here - I don't mean to be - but have you ruled out an affair and/or an OM? I'm not suggesting that's what's happening. But anytime I hear of a sudden change in a person's demeanor, that's where my mind goes. I've gone through it TWICE with my H.
Hang in there! We're all here for you!
M: 40 H: 44 Married 14 years S11 & D6; D20 & D19 from previous M 2BDs/PAs, 8 years apart Piecing: April 2014
