Do you in fact mean you are 'tenants in common' as joint tenants is what most people are. Do not sound apologetic for being whatever you are, you are just as entitled to benefit in the growth in the value of the property as you have been caring for your child and contributing as you can. This is not a trained legal opinion, someone else may give you that, however I do not think there is a hope in hell that he would be able to argue that the current home is 90% his. In fact he would probably have to buy you out as you would probably be able to remain there with the child. Not being married makes things a bit less clear cut, but do not be bamboozled into doing anything hasty and if things did get 'nasty' make sure you get the proper legal advice. Best thing is to be fair to each other and reach an amicable agreement without involving solicitors, but you maybe should get a one off advice session so you know exactly what your rights might be.