He goes soft when putting a condom on

Things between this guy and I have been getting pretty serious. We finally started having sex but I’ve noticed that when he goes to put the condom on, he starts to lose his erection and goes soft. This is pretty frustrating for both of us 😬

this happens every single time he goes to put a condom on. This has never happened to me so I have no idea what is going on...

Are there any tips or advice y’all can give me?