My XH is a nasty abusive twat :(
We have 2 DD's (9 and 3), he does see them, when he can be bothered and when he isnt working abroad.
We have been seperated 4 years and divorced 1.He has NEVER contributed financially, not even when we were together and not a penny since he moved out.
I have been paying all the joint debts from hus business which has finally been wrapped up.
Luckily I have a good job and we have survived but its been hard at times (and I almost lost my house).He seems to have walked away scot free.
He has worked erratically since we split and it never seemed worth the hassle of pursuing. But for the last year or so he has worked consistently abroad for months at a time, earning I am sure not an inconsiderable amount. I have paid every penny for my girls and paid all our joint debts. I have significant debts left, a credit card to bail us out when things were really bad, a looming tax bill, and large solicitors fees :( I work bloody hard.
So he is back for a few weeks over xmas, and I gently bring up him paying some child support, I suggest very reasonably I think, that he only pays me the weeks he works and an amount much less than I worked out on the CSA calculator.
I got an earful of abuse and sneering, he just cannot see why he should pay anything when "you earn XX a year" 
. He has no sense of responsibility at all.
I am not going to let him get away with it (if he can afford to buy DD1, himself and his GF £300 Ipods, a massive widescreen TV etc etc), then he can afford to support them, even its just enough for school shoes/uniform, music lessons or childcare etc.
I thought I was past him affecting me, but I am absolutely terrified how he will react, I have almost completed an online application but am still hesitating, what happens next when I do it?