Major boyfriend Problems? Please Help What to Do?

So me and my boyfriend have been together for a year and a half. The one issue with our relationship is he always seems to freak out before big events, meaning before homecoming, prom and other big events and now before my open house, meaning he breaks up with me than back together with me before the event. Well he broke up with me two days before my open house even though just the day before that we hung out and it was all ok. Well today was my open house he didn't show even though i thought he might. The thing is he always comes back and idk what to do. Should I text him or leave him alone for a while? Also his sister just came back from spain two days ago from being gone for about two months and he did mention she had wanted to do a barbeque today because she missed fathers day but he knew how important he was to me. Idk advice what to do? My friend said to just not text him until next thursday if than...