I think you need to be careful here. How have you decided how much your husband's share is ?? Just being cautious for you, as you are only separated and if you are not divorced then there are lots of things that have not been addressed ie. the sharing of your pensions, maintenance, all those things. If you enter into another binding contract with your partner just thinking that you might have wished you had sorted out the marriage settlement first as if you and your partner did not work out you could be in a very difficult situation. If you are quite happy with all that then someone else can advise you on the legal issues.