Steve: Hey, if you're a sex-only partner only, you're in! Until he finds something better. Which he will. No one, alas, almost ever lands marriage from free sex. Put the sex aside and find the right man. If he wants sex first, you need another man.
Mia: Tell him that you want more. If he says no or that he's not ready, then close down the candy shop. Then, no matter how much he begs — and he's going to beg — don't give in. If there's more to this relationship than just sex he'll make that clear to you. If not, keep the candy store closed and don't open it until you find the loving, committed relationship you want and deserve.
Mia: No girlfriend! If you're jealous of his having a baby with another woman now, you'll be even more jealous once the two of you share a kid. Money that could have been spent on your future kid is going to have to go support another household. Are you cool with that? I'll bet not. Until you resolve these feelings, don't make any babies with him or anyone else. Get counseling to help you come to terms with this situation. It will not be easy and I wish you luck.