My dude, it happens.

You're not alone and it's usually an issue of anxiety and nerves.

You can talk to a medical doctor, you can take to a sex therapist, read up about sex performance.

The main thing I'd advise: be patient and present. Listen to your body, don't get too stuck in your own head. Have fun and enjoy intimacy, and maybe even just take PIV off the table for a while. This can help relieve the pressure you put on yourself.

Alcohol and cigarettes make it worse, so the usual: mind your diet, sleep and exercise.

Consider laying off masturbating as you sort this out. Sex drive does build over time and masturbating can reset that drive as well