My hormones are makin me crazy.

I'm only 9 weeks anc my bf has a kid with another girl and I don't mind that they talk, ya know? I want him to be involved in his sons life. And every time they talk im super okay with it. But lately I swear they talk like normal adults and I am constantly thinking "what if he wants his family with her back?" Like what if he leaves me. To the point where he left for work the other day and I started crying out of fear that he will leave me and go back to "his family"