I'm a little confused. You say you want to have HIS baby, but you mention the two of you will be living together. So, would you be a surrogate or would you be the baby's mother? It seems you are actually talking about co-parenting and I'd wonder if you're really ready for a baby?

It sounds as though you are more attached to this man than is fully healthy because you are not in a relationship with him. He wont always be single and you wont always be living together.