I dont think £250 for 2 kids is a huge amount, however I also don't think that the absent parent should be fully responsible for all costs. Even things out, stick his £250 a month in a pot, chuck in £250 from you plus the child benefit then its a bit more equal.
I'm not saying by the way that you should actually do this but some replies seem to go down the road that his contribution should cover everything.
I don't think his contribution should cover everything.. they are my children as well and I see it as my role as their mother to provide for them. I just don't see why he thinks 250 quid is enough for 2 children and expects me to provide everything else just because I'm entitled to benefits.
Thank you all for your replies. I still don't think I was in the wrong for asking. But he always will. 1 of the many reasons I'm glad we split up!