This is the issue with LDR - you guys need constant communication. The moment communication slows down or changes, either one of the parties will suspect the other is seeing someone else. Because you guys are not together in person like that, hence having that line of thought. I've been there before in a similar situation and it certainly didn't feel good. It did put me off social media for a few months because I kept getting anxiety from the entire situation.

Best find a relationship that isn't LDR. One where you guys can meet at least 1-2x a week.