How to stop being jealous of the "babymomma" πŸ˜πŸ˜’

My fiance has another child with a woman. They did not have any kind of relationship- a 1 night stand in fact. I met him when their daughter was just 1.5yr old. So of course Im aware he has a child,and after learning about their rare circumstance,I wasnt too worried about being jealous of this guy having a "babymomma". I mean,he didnt like this lady, she didnt want him,and they are strangers, 4 years later they still dont know eachother. Sad almost.

Well anyways, my issues are just my own. Somedays I struggle with this other woman. My fiance and her obviously have to comminicate, and Im being petty and maybe childish,but I dont like it. Its just the fact he has to constantly talk to this lady. You wont get it,unless your also in my shoes. Just looking for any ladies that know how I feel...I wanna be the only woman in his life, im just trying to accept its not that way.