Feeling lost at the moment

So my boyfriend and I haven’t talked since October 30, 2018. Keep in mind that we have been dating since September 5, 2018. (We have know each other for 4 1/2 years.) When I last talked to him he said that he found out some devastating news when he went into work. I didn’t know much details and that was fine by me because I understand that somethings we don’t want to talk about. I told him I was here for him and his family. So over the course of halloween weekend he said that his sister would have his phone because he was heartbroken and etc. Remind you I’m still worried about him but say okay I understand. I kept trying to reach him on December 11, 2018 because I was going through losing my brother who died in a car crash on 12/8/18 and my best friend passing away from cancer 12/10/18. I wanted him to be here for me through that but got a response from his sister which came off as her being rude and having a attitude. Fast forward to March 9, 2019 and I’m scrolling through Facebook (which I don’t use a lot) and I see a post that he made that said, “I’m so happy to be down south with my family. These next few months are going to be good even though I have a lot to look forward to.👫👶🏽” when I saw that post my heart broke into a million pieces because I don’t know if he has been cheating on me the whole time (which I don’t believe so.) I just don’t know anymore. Maybe I should break up with him.