Mediators are professionals who can help you and your partner negotiate an agreement on how to financially support your children and other financial matters.
Mediators cannot give legal advice - you may like to take the advice of a solicitor as well so that you can discuss things in mediation against a background of knowing what your legal entitlements are.
See Useful links for details of how to find a mediator in your area.

Read how others coped:
Daisy
Daisy
'I wanted to keep this amicable and hoped we could sort things out between ourselves without getting lawyers involved.
But my soon-to-be-ex is very competitive and I think he sees this as some kind of point-scoring game where, the less he gives away, the more he is the winner. He really doesn't get it that it's Seb, our son, who suffers. I'm going to try to get him to come to a family mediator which I hope may diffuse some of the confrontation and help us reach some kind of agreement without spending all our savings on legal fees.'