Should i be mad!?

Me and my SO had an agreement that we would close our facebooks since it was so time consuming when we was trying to spend tome together, his cousin came for vacation and convince him to re open or make a new facebook and he did, he didnt tell me about it untill now, shouldnt i be mad? I mean he practically lied or what ever, he didnt tell me and  just upset about it, what you guys think?