Long distance open relationship?

So my boyfriend and I have been dating for about 3 years now and this is our first year in college away from each other. We’re about 8 hours apart so I don’t get to see him very often I’ve seen him 4-5 times for the last 4 months. About 2 months ago when we saw each other he told me that he still wants us to be together but he needs the physical aspect of a relationship that I can’t give him since I’m so far away. He suggested that we break up and see other people but still be best friends bc as he puts it in the end we will be married and happy and this is just a small bump in the road. We talk about getting married and stuff a lot of hearing this made my heart break. But I agreed and now 2 months later I feel like I’m dumb for doing this but I know we love each other so much. He hadn’t actually done anything with other girls yet but I just can’t imagine him with anyone else. I don’t know if I should continue this relationship anymore. What should I do? Any advice is welcomed.