I was in a well-paying job before DS was born but I chose to stay at home with him after he was born. Every time I ask DH to parent DS - sometimes to give me a break, but most of the times for DS to bond with him - he says I chose to stay home so I should be doing all of the child care, he says he would participate if I was working too. In his mind, he thinks since I "stay home ALL day" (his words), it's unfair to ask him to participate in parenting. I've had many arguments with him over this and I think it's just a waste of my energy since he's not going to change and asking him to do something just makes him that much more stubborn to comply. When he does, he does it so begrudgingly that I hate to ask him anymore.
How can I make it easy on DS to get used to babysitter while I'm away?
Wow. So does your dh not like his kid? Does he ignore him when he is home? In this situation, I wouldn't want my dh to watch my child either. But you can't be content with that. It is important for you to realize that this is an extremely unhealthy dynamic, one that will only get worse as your child gets older. If my husband did not like my child or acted like being a parent was such a huge chore, there is no way I would continue to live with him.
Is going back to work an option for you? Even part time? I have no real suggestions on how to make it easier on your son to go with a sitter. Usually I would recommend leaving baby with dad on a regular basis to get him used to separating with you, but apparently that is not an option here. Can you try the gym thing again, and just go for 5 minutes the first day, 10 the second, etc etc?