Update: Random girls on my block list?

Today I noticed girls on my block list. I've never seen these girls names in my life so I know it wasn't me it was my bf. I've let him on my phone a few times. They are obviously girls he's been with/talked to when we weren't together but I duno wah to think though does this mean he has something to hide that he doesn't want them to tell me? What would you think?

Update: I confronted him and he said they are all girls he used to talk to and that he blocked them before we even got back together so it's not because he's hiding anything. Even swore on our unborn babies life. (We had broke up for 6 months and both met other people) He said he did it because he wanted a 'fresh start' and that he blocked them on his own Facebook too. I honestly don't know what to believe. Does his answer sound reasonable?