Any Advice?

He went soft in my hands for the first time. Were on the couch and I had been teasing him for the last hour. Licking fingers and sucking. I went down on him, got him off and began to play with him afterwards. He went soft in a matter of minutes. We did have sex 4 times earlier in the day although. Our year is next month and we just got a place together. Am I doing something wrong? Or Am I overthinking things like I usually do?