sex for long time(1hr),but after doing masterbation i got ej

hi i am 24 yrs old male, just now only i am doing sex with my girlfriend, but i do for 1 hr but i didnt get any ejaculation feeling, but if i masterbate i got ejaculation. i cant do very fast also. what can i do. for that.....

It's a very common problem that can be solved if you ask your GP doctor about it and try
spending more time on foreplay( playing with each other) like for example touching and caressing each others bodies so you both can get aroused. This may help make ejaculation easier i think, or alternatively trying a different sexual position.

You didn't say if you were using protection, a condom, or any other form of birth control.

You may be feeling stress, being new to intercourse and all...
or you may have the sensations being dulled by a condom...
or you may have used up your current supply of semen by masturbating.

Masturbating prior to intercourse tends to make you last longer, and delay, if not defeat ejaculation.

But I must point out, if you're practicing un protected sex, it doesn't matter if you ejaculate or not. It just takes one sperm to swim up stream to make her pregnant.

USE PROTECTION EVERY TIME.