ACJ...I do know how you feel...my H moved away from me...we had 3 children also...he didn't call, send support, visit, or email but a handful of times over the 18 months he was gone...
I thought the same thing...how would he know of any changes I made...this was actually a motivating factor for me to make the changes that "I" wanted in myself...
But in the few interactions we had he did notice...I not only was a good mom but became even a better mom while he was gone...and I had written into our S/D agreement that if anything happened to me he DIDN'T get the kids...and HE SIGNED THIS!!!...he did give up everything...so don't think you are enabling his current lifestyle because you are being a good mom and doing what you need to do for you and your children...
Just keep it up...GAL...do things with your kids and friends...make changes that YOU WANT...this will empower your own feelings of self worth...because I know how low I got...it wasn't a pretty sight...