Live in BF stayed out after work till midnight!

Live in BF stayed out after work till midnight! I texted him at 945 asking if he will be home soon and 20 minutes later he said “yeah will be home shortly”. He didn’t tell me where he was and if it weren’t for snap chat and seeing he was at a friends house I would think he was cheating. Anyways “shortly “ ended up being after midnight! I pretended to be asleep and then slept on the couch. I am not the over reacting type of GF I am 37 after all but do I have a good reason the be pissed?

! 😡