I understand your concerns, masturbating does not cause impotency or infertility
Masturbating is different from real life sex. Even if you have delayed ejaculation during masturbation
it doesnt mean that there will be delayed ejaculation;
In real sex there will be a lot of foreplay between you and your partner which may give full satisfaction to both of you.
Try to keep some masturbating free interval(say 1-2days) between to have a good amount of ejaculaion.
Just get the stress
out of your mind. Practice Yoga