Might sound funny but i suggest seriously trying this: Eat 7-10 eggs every day. Could go even higher if you are a bigger guy. Personally i boil them. It might be placebo but i feel it really just boosts your ability to more easily get erect and get stronger and more lasting erections. Also how many times you can bust in a single session without feeling too exhausted. I really feel there is something to it, i think eating a lot eggs is like one of few actually working aphrodisiacs. And the quantity really does make a difference, really has to be 7+ eggs. I eat like 5 or 6 but the ones i get are like double size of a normal egg and have 2 yolks. So yes, i eat 10-12 yolks a day. And don't worry about it. its healthy And also i've heard about this a few times from others as well.

Also you shouldn't care if you don't initially get an errection, its only bad if you let it affect your mood, take the lead and get her to suck you until you get hard (some women actually prefer starting to work on a flaccid penis and have it grow because of what they do), if she doesn't cooperate then just try with other girls and eventually you'll find someone who it will work with and, and also yeah, quit the masturbation for good too. The stamina/lasting issue should just sort itself with more experience/practice, with the same partner or in general.

Wear a condom. I last whenever I want.

Hate to be crude but do you masturbate? This can be just as bad as porn. Try no masturbating, no porn for one/two months and you should get hard no problem/go multiple rounds every night. Even soft-core porn like Instagram thirst-traps are bad, cut all that shit out. Forget what andrewtatespancreas wrote, porn is fucked and causes heaps of ED read the studies.

Before taking proper medications like viagra/cialis I would start taking shitloads of zinc, multivitamin, fish oil, eat a steak, get some sun, lift heavy weights and try and have as little body fat as possible. Give it two weeks.

Are you fit/ have a good body? Maybe you are a fat shit and know it and deep down inside feel insecure when you get naked.

Some guys need foreplay to get rock hard, so maybe spend about 10 minutes foreplay. What turns you on?

What happens after you cum early? Just wait another 15 minutes and go another round.... You should be able to go at least a couple rounds a night if the girl is hot enough/ you are medically healthy. Maybe the girls you are hooking up with aren't attractive enough for you.

Switch it up during sex. If you feel like you are about to cum early, stop, pull out and start eating her out for 5 mins, then go again, rinse and repeat. Try different positions which don't make you cum as fast. Switch positions regularly, there are definitely some which make guys cum faster than others.

Don't fucking be upfront about this shit with them ever. Wrong move my dude. There's nothing wrong with busting a nut early. There's nothing wrong with taking some time to get hard.