Any help?

Okay ladies so I don’t know why every time me and my boyfriend have sex he finishes too fast or can’t keep an erection for more than a minute sometime its hard to get his 🍆🍆 hard🤦🏼‍♀️ I don’t know why and its frustrating because we can be having sex and his 🍆 would die instantly 🤣 so what could it be ? He is only 22 years old. I been telling him to go to the doctor to get that check but he always working😭 When we started dating he would cum fast but his erection would last more now is different 😖 could it be me the problem?