T0, I would advise you to stop trying to get into his head. Stop worrying about why he came back the first time and instead think about why y'all didn't work on things and change things enough for BOTH of you to stay happy.
These are improvements you can make in your*self* to make you a better, happier person and (eventual) partner, whether that's with H or someone else .
M: 40 H: 44 Married 14 years S11 & D6; D20 & D19 from previous M 2BDs/PAs, 8 years apart Piecing: April 2014