Maybe it is because he has a direct line of communication w/you and he doesn't have to "rely" on communication w/the children in order to feel "close and/or near" you. I know, it sounds crazy, but sometimes just being in touch w/the children keeps that one little strand of thread in place to the spouse. Maybe he has a way of slipping in comments or asking indirectly about you and what you are doing. Maybe the children are sharing some of your life w/him and don't realize that they are doing so.
It's had to say what is really going on in their minds, but some day, he might be able to tell you more about this...but that is much further down the road, if ever.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.