Should I write to my ex who’s at boot camp?

Hi everyone,

My ex-boyfriend and I broke up in February and haven’t talked since. The past few months we’ve both been seeing other people but I keep finding myself thinking of him and missing/realizing what we had. I tried to reach out to him before he left for the Marines at the end of June, but it didn’t get very far. I really want to let him know how I feel before I start college at the end of this month but he doesn’t graduate from boot camp until October 5th. I already wrote a 4 page letter explaining my feelings and giving him encouragement to get through the rest of training, but I’m 50/50 on whether I should mail it or not. Please help! I don’t want to distract him but I really want to let him know the way I feel... Any advice would be greatly appreciated! ❤️