Masturbation Vs Actual Sex

Kai • Hello Im Kai. Me and the hubby been together 4yrs married 1 year. I have a 9yr old girl but Trying to conceive and start our full blended family. Here for support.
This is random but why it seems to me when I masturbate thinking of my hubby the love we make or when I watch porn I cum in like 5 seconds Lol but when we have sex it takes longer like 20mins to a hr. I know I'm not the only one cause my friend said she's the same way. Any other ladies agree? If so why is that lol