Sounds like he is still trying to come to terms with the decisions he has made and wants to keep a connection with you. For some reason you are the connection to the children, perhaps because he didn't put in the time to have a real connection with them himself. You have a great strength to just address the facts and not get too involved.
H: 48 Me: 47 Married: 19 yrs T: 20 yrs 2 teen-Ds and S H-MLC (started 2012) and H-Unemployed (11/2014) D-Bomb: 2/2015 H left country but hasn't moved out: 7/2015 I filed: 7/2015