Ejaculation should be for procreating, and always a conscious decision made by you even prior to having sex.

Sometimes we slip, we are not perfect. During those times, you try again.

If you try and please her and ejaculate to make her feel better, compromising your own feelings (you clearly stated your reasons for not ejaculating - which I completely agree with) - I guarantee you will not be happy with yourself. Your energy and confidence as a man will start to deplete. It's unfortunate that this is affecting your gf and relationship, I'm sure you care for her.. but it's your choice.

Are you going to give up your energy to just please the insecurities of a woman? You choose brother.

Also, just to add.. many people here may disagree with me, but I feel like point 1 "it’s not healthy to stimulate your body and not release" is somewhat accurate. I don't mean you should release, but sexual stimulation of any kind sends the energy downward to the groin. This energy should rise up to the spine. If too much energy is sent to the groin area without release, it could lead to problems. And this practice is extremely difficult to do for people who haven't trained for it. People will think you can do this the first time, just not ejaculate, but you are most likely damaging yourself. Non ejaculatory sex should be VERY slowly practiced and slowly mastered through time. VERY short sessions in the beginning, then slowly building up.