Suggest Treatment For Improving Penis Size

Hi Yes I am 40 yrs old and have recently been in a relationship which was finished by my girlfriend as she was not happy with the size of my penis. 2 years ago my wife of 7 years left me as she said the same thing. My sex drive is quite high and am able to satisfy women I have been with by oral sex etc and but now I am feeling really low as I have been rejected by 3 women now due to the same reason. Is there any way of enlarging the Penis? My penis is about 4 inches when erect and less than an inch when flaccid! I have tried the jelqing method for a long time but with no obvious result. I need your help as mentally I am a wreck nowat this stage.