Jealousy strikes

A part of me wants to have a baby with my boyfriend, because he has a kid with someone else, not to take away attention but because i feel like im an outsider. And i get really jealous, for the fact her mother constantly writes and emails my boyfriend inappropriate things on a daily. i absolutely love his daughter but i just can't help it.. i get in really depressed moods when i see them bonding... because i recently had a misscariage.. It's horrible of me .....