buying house and TTC - please help so confused

My partner and I have just started trying for a baby and just started to buy our first house. I don't have any money to contribute to the deposit so my partner is saying that if we split up, we both get back what we put in. As in he gets back his full deposit and I get back whatever I have contributed to the mortgage. I would agree with that normally apart from trying to have a baby. What does everyone think? I don't know how to quantify the work I will do in carrying a baby and don't want to be left in a terrible situation with a child if we did split up. I really need advice from all you experienced ladies please...