What do you think?

So in August I'm moving across the country and my boyfriend of 4 months does not want to do LDR. He wants to break up when I leave. Part of me understands because LDR isn't easy and we haven't been together long. But part of me can't understand why he'd stay with me for any other reason than sex when he knew me moving was a possibility from the start! He's super supportive, randomly calls to say hi, shows up at work with coffee and all sorts of other stuff. He's so encouraging of me leaving because I'll be following my dreams but I just can't understand it. He's never said I love you (but neither have I) which makes me wonder if he's only in it for sex. What do you think?