Because you don't watch ****

Try ********** a few hours before, watch ****, try distraction technique, try stop start technique.

But are you inexperienced? .. like sex and lasting takes time to master. Sex isn't simple and easy and fun like in movies, and not even like 18+ movies.( ****, adult movies, Hollywood, soap operas, reality TV are ALL Scripted) Do you pleasure yourself often? - has been proven to help improve maintaining etection, and also regular mastrubation minimises the chance of cancer. It's a natural need to "empty" at least few times a week. If you haven't had a lot of sex, and don't have a lot of partners, and you don't mastrubate then by all accounts you might be an adult man, but your privates are still in inexperienced teenage phase. All this needs is practise, exercise, maintain and learning what triggers you. If erection doesn't last after giving more training opportunities, seek medical professional such as urologists if you think it's physical, sexologist if it's inexperience and or mental, gym/Pilates/yoga as it might be just overthinking it and your muscles flexing/cramping due to increased physical activity and you finish faster. Either way putting yourself down because your body isn't perfect is toxic, and could I please offer that before you end up in bed if it's someone you care talk to her/him before of your worries of lasting long enough, and maybe explore other pleasures to extend the fun, or after you finish continue pleasuring your partner, or if you always finish first, maybe make the partner cum first and then let yourself finish. If its one night stands then you got what you needed and her storming out angry or happy is irrelevant as you fulfilled your purpose. Never apologies for something your body does, it's maybe embarrassing, but not something to measure your worth in.

go to the bathroom and rub one out real quick first. they'll never know.

Are they upset that you came too fast or are they upset that that made the encounter go by too quick? If it’s the latter, see if spending way more time on foreplay and getting them to ****** first will help ease hurt feelings. As for the former, aside from the other advice in this comment section, maybe see your GP just in case to rule out health-related causes?

strengthen your muscles. Like kiegel exercises. Stop your pee flow while urinating. repeat. repeat. do it all day while at work. build up that muscle. Will help you to hold back during sex. Also, could be anxiety-induced. You're so worried about premature bust that it kinda becomes a self-fulfilling prophecy, so to speak. Try different procedures. Like, foreplay first, get her to do oral on you, get the first one over with. While in your recovery phase, go down on her for a while. She will like it. Then try again after she busts off.

Can't you try again? The times you cum after the first should be a lot longer.

You did everything but see a GP. Get checked out for premature ejaculation.

Practice your foreplay, give her an ****** or two and she'll be less bothered by how long you last (absolutely not speaking from experience)

Read what Blobby McGee wrote, and re-read it, and make it your daily practice. You can easily practice this 5 times during a normal stream, and whatever, x6 times a day. It's a huge muscle group, and you'll feel it first just at the base, but the more you work it, the further back you'll feel the ability to control the muscle. Then you can practice this when you are pleasuring yourself and feel you're close. It's the only thing that works, but it 100% works.