getting over the fear of falling in love

Natalie
How do y'all find the courage to trust your S/O to stay in your life? 
I am falling in love with the person I'm with, but I always over think things and I'm so scared he's gonna leave and I'm gonna get hurt. 
Any tips on getting over that fear ?? 
Thank you!! 😘
Back story: 
So I have had this fear of trusting people to stay because my dad had a few girlfriends while I was growing up, and they were the female/ mother figures I turned to.. but as relationships do, they ended and now I have some issues trusting people.