It’s hard to say why you’re blocked now because there could be a ton of different reasons, but what if one of them caught the other checking up on you and got in trouble because of it? So they agreed to block you to show it wouldn’t happen again. That sort of seems like the most logical explanation to me, especially if you know they’ve been checking up on you. And just remember… your friends can’t really know what goes on behind closed doors either. Sometimes even partners don’t know, which is why so many people get blindsided by the ending of relationships or infidelity, especially, because people don’t tend to broadcast that if they don’t want to get caught.