I am not going through a divorce right now but did 4 years ago.......man I can not believe it has been that long. My husband was somewhat the same way always wanted to be out at the bar or at his buddies house and not home with me and the kids and I got sick of it as well.
Here is advice from someone who has been through this and survived:
First, the money issues. I totally agree with you that other things should be taken into account when figuring child support, but they are not and that is the way it is and we just pretty much have to deal with it. When we got divorced I was in the same boat, 650.00 house payment and 425.00 car payment. I had to sell the house and rent a duplex (was it what I wanted, no....it did not have central heat and air and there was no shower , just a tub and there was not a dishwasher) but it was what I could afford and we dealt with it. I got rid of the Yukon and got a Ford Focus, much lower payments and much cheaper on the gas, again was it what I wanted no, and three kids in there was pretty tight but we did it. My personal advice is that I waited too long to cut down my bills and do these things and got far behind and damaged my credit. Make some changes now!
As far as him seeing the kids, I know all to well how that is also. Since your oldest is 17 maybe you could talk her into going to the visits for the sake of your youngest so she does not feel so alone. Just tell them that is what the judge orders and he is in charge of the way things go. I have learned that I can not be upset or worry about the fact that their dad is not around. It is not my job to cover or make excuses for him either. Why doesn't daddy come to my games, scout stuff, school performances, birthday, etc? I now tell them they need to ask their dad and of course he lies to them. Over the years my children have caught on to him, and when they are older they will have him all figured out without having to say a word or bad mouth him, kids are smarter than we give them credit for. Your kids will do the same.
I finally decided to go on with my life not worry about him seeing them or attending their functions, do what I know is right for my children and be there for them and they will remember that.
If you would like to talk more I would be glad to help you through this or give you any advice or talk more about what happened to me please shoot me a message!
Good Luck, S.