21 y.o. need dating advice

So I met a boy last Fall and we had feelings for each other, but we didn't do anything about it. And it was rough because at one point I stopped acknowledging him and my own feelings for him, and it really hurt us. Then he left to study abroad in the spring. But now he's back. And we still have feelings for each other, but I just feel like how I feel about him is too serious to just be dating him in college where most things don't feel like how real life works. And there's pressure in my chest the whole time when I think abt him. Because he already left me once and that broke my heart every single day for 8 months straight. And I'm still shaken. Every time I thought abt that I just feel paralyzed by the feeling of helplessness. And I think he has the same kind of scar too even if he doesn't talk abt it. Boys do that a lot. And I don't want him to. I really love him. I just want to know how to get over this so I can start something. Because I'm gonna to marry this person. I refuse to be like this.