I fell in love with the right man at the wrong time.

My current boyfriend is now moving 4 hours away for school and the thought of another long distance relationship terrifies me and I don't think I can do it. Just thinking about it makes my heart drop and makes me feel sick to my stomach. I don't know what to tell him. I can see my future with him (getting married, having kids) but I can't see this long distance relationship working (I'm way too insecure and scared from my past relationship). I don't know how to talk to him about this or if I even should. I know he'd get sad to know how I'm feeling and I don't know if letting this amazing relationship go will be something I'll regret just because of my past, but I also don't know how I'll handle the long distance. I used to cut from how sad I was in my past relationship, I'm so scared of spiraling down again.