Feeling his penis throbbing inside me but he didn’t cum?

I was having sex with my husband last night and he was about to cum so he stopped thrusting because he wanted to last longer but his dick was still inside me. I felt it throb during that moment but he claims he didn’t cum and I trust him but I never felt a dick throb inside me in my whole life so I’m a little confused lol. Do you think he actually came? Or maybe he was making his dick jump because he does that sometimes when I give him a bj but never inside me.