Sex is as much mental as it is physical. Just relax and try to clear your mind and enjoy the experience. Putting pressure on yourself only leads to problems.
It also should not end a relationship. Only more pressure and stress. I would hope your relationship is built on more than just sex.
Perineum is a small traingular muscle between anus and scrotum (male) and between anus and vagina. This is hot spot for male and female. Dip your fingers in the perineum and find out the spot which gives pleasure to you.
massaging this spot with pore of your fingers will produce orgasm.It will take some practice to find this point.
While doing intercourse, you may lean on her rubbing her clitoris with the dorsal part of your penis. This will give extra pleasure to her.
For increasing sexual energy you may do satkriya. Search the word sat kriya or satkriya. This kriya(action) will increase the sexual energy.This is a part of kundalini yoga.
Our relationship is based on more than just sex... however sex and sexual desire can be the difference between friends and lovers. The problem surrounding this is my girlfriend has had a failed long term relationship in the past where it was someone she cared alot for, but there wasn't any sexual desire from him as time went on... at all. so she is trying to avoid that happening again. our situation isn't the same by any means, but its having the adverse affect of bringing that back for her, and a fear that its because of her.
Not the case however... im just trying to find solutions for my issue so we can move on and get back to normal and giver!