You can do the stop/start method with your partner, having her stimulate your penis and stopping when you become too excited. It’s the same exercise you have done on your own, but now you do it together. She can first do it with her hands and later on with her mouth, if she wants to.
During intercourse it’s better to use deep, short thrusts or a circular motion than deep long thrusts.
Guys who have control over their orgasm during intercourse don’t thrust vigorously all the time. They make subtle adjustments during intercourse. They go faster and slow down. But they also vary the way they move. So if you want to delay orgasm during intercourse you can start by not moving for a while, while your penis stays inside the vagina. Resume movements if excitement has decreased and you are ready to go on. If this works you can try to make subtle adjustment. You can for instance change pace or vary your movements. Instead of thrusting you could make circular motions, stimulating your lover’s clitoris with your pelvic bone.
If you feel you approach the point of no return but don’t want to come yet, you can also use the squeeze technique.
Some men have better control if the girl is on top, so you could give this a try. Ask her to stop moving when your orgasm comes too close. In the meantime she can stimulate her clitoris and resume moving when you are ready.
It might also help if you feel less pressure to perform. So satisfy your lover beforehand, by fingering her or eating her out. If you then come quickly it’s not such a big deal.