I understand how frusturated and sad you feel for your children. It took my children 1 week to even realize their father wasn't living with us anymore. The truth is this is one of those situations where you just have no control. In fact, the more you push for it the more your husband will resist it. Just take comfort knowing that they are lucky to have such a strong, loving mother in their lives. (Some kids don't even get that).
Your husband has to miss them and become a better father on his own terms. I noticed that after a couple of weeks of me not saying anything my husband started initiating more visits with them (but this might just be because of legal advise and not wanting to pay child support).
Yes, arrange it so you could go to baseball game with son this way if your husband is not there he will have someone. Or perhaps there is a male figure in his life that he adores (grandfather, uncle) that would be able to make it? Don't call and pressure husband though. It will just push him away. Sad and wrong I know but maybe look at the situation with empathy for your husband. How sad for him that he is missing out on the children's lives, that he just does not know any better, that one day he will have to look back on his life with regret
Me: 42 H: 43 Twins age 5 Physically Separated 7/2015