I'm just guessing here... Because I can identify with a lot of what Emilie is saying.. The "Screw you dude- screw you" line had me laughing, because I have said it to my self so often.
I'm not sure what to tell you - I have felt just like you did so often (although I'm the one who works outside the home more than dh (d?) does, and he stays with dd more) But I do also feel like I am more emotionally invested in our relationship, and have to 'fight' for 'us' time - away from the TV instead of the computer in our case.
I also would have been gone a long time ago if it wasn't for dd. It goes both ways - I don't want her to see us fight and not get along... but I don't want to rip apart her family - she loves both of us so much! This has been going on for most of her life - she's just over 3 yrs old.
On the other hand, I know I am not perfect. I know that running away from this relationship without trying to work things out will follow me into other relationships. I have a good friend that's divorced and have said numerous times that knowing what she knows now, she wouldn't have gotten divorced - because of how spiteful her ex is and their custody issues. Not saying you should stay in a marriage and be unhappy, but you also have to realize he'll always be in your life as your son's father. Unless you think he would not want to ever have visitation, you'll have to deal with him for a long time to come. (and any future girlfriends, wives, etc)
Now I'm just rambling. My h and I had a fight last night, so my attitude is a bit tainted by that.
to you. sorry for the rambling