Is he pretending to cum in me?

My man and I have been together for a while, and It’s been his idea to be trying for a baby. But I don’t really ever notice any major leakage after sex, and he does go to the kitchen immediately after… I always assumed to wash his hands or something but could he be going to finish himself really quick but wanting me to think he’s finishing inside? I know this sounds paranoid af but I DO think he would be offended if I asked him. Has anyone ever encountered something like this?