Why doesn’t my boyfriend want to add me on social media especially Facebook?

I find it weird. We been together since June; never have I been crazy and did anything wrong for him not to want to add me. He has all these girls because I see them hearting his stuff. The last time I asked about adding him he said he doesn’t use it but I told him he’s lying and wiped it off. He gave a petty ass excuse of “old pictures” like why does it matter. We been together I’ve seen him before it’s weird to me. We aren’t from the same town he’s not even from this state but moved here about a year ago. Where he lives he has all these females what do y’all think? Am I overreacting because he doesn’t want to add me?