Husband lied about a girl from the gym

Should I be upset? Me and my husband have been together for almost 6 years. We’ve never lied to eachother and have always had a very honest relationship. The last few months he’s been going to the gym for a 3 hours around 7-10pm. He goes to the gym right by our house but during a conversation last week he mentioned going to a gym a few towns away, which he never told me about doing previously.. that gave me this weird feeeling in my stomach. My gut feelings in previous relationships was always right.

Friday I took him out to some bars for his 30th birthday with some family. A girl came up to him all excited to see him and he acted like he didn’t know her and she was like how don’t you remember me? I was standing right there so I asked him who she was (I’m not confrontational at all so i didn’t ask it in a rude way) he automatically said he had no idea. A few hours passed by and all of sudden he said he met her at the gym. His friend at the gym brings his gf and she brings her best friend so they can all workout.

Is that not weird? A couple that workouts together brings a single girl to workout with a married man? As of like a double date? Lol

Idk what to think