Scared

I’ve been with my boyfriend for a year and a half but is it weird to think that I’m still scared that our relationship won’t last? At first, I was scared and I’ve learned to let go and not think so negative. But I’ve been having those thoughts every now and then. I feel like the reason why is cause I’ve heard people breaking up or having a divorce. I know my guy is a loyal kind of guy but I also know that there are other girls he might be interested in. I know that when you have a significant other, they’ll love you no matter what and that sure, they could be your soul mate. But if there’s a saying that there’s a couple people out there that could be your soulmate as well or someone you’d click with easily, it’s easy to say that there may be someone else that he’d be interested in. How do you keep telling yourself to not think so negative?