Should also include I am over weight but have seen over weight guys on internet have sec with women on internet....
So in sure this could be a factor but I feel its not the main one.
Your answers are in your comments. Your compulsive masturbation is sapping much of your sexual energy and not leaving enough for your time with your partner. Your sexual needs have been overtaken by a habit. Cutting back on masturbation and porn will help, but you may need to avoid masturbation/porn entirely for best results for a long-lasting relationship. Your weight is the other factor here, and getting that under control should also help ED problems, beyond overall health, energy level, appearance, and so on.