He got soft?

My first time having sex with someone well not in a relationship he couldn’t keep the boner and the sex was so bad I couldn’t stop laughing...whoops. He claims it’s because he masterbated earlier that day and that’s why that happened (is that a real thing) but after like 40 minutes of sex hell basically and me guiding him trying to get myself off he came too soon for me and then left 😂 I hope I never go through that again.