If you weed out the small percentage of RE cases caused by the fairly obvious and dramatic reason like sexual abuse as a child, strict religious upbringing, organic disease, and fear of pregnancy or disease, you are left with a majority of cases for which the specialists
find themselves stymied as to what method of treatment will actually work.
I can not think of another male sexual dysfuntion where so little real
research and proven knowledge is so sorely lacking. This gives rise to a whole host of bizzare treatments and theories, many of which are to be found by typing "retarded ejaculation" into a search engine.
Perhaps sexual researches should start by looking at why a man DOES ejaculate into a vagina rather than why not. He does so because he is extremely aroused. Some retarded ejaculators will say they are extremely aroused too, but I think this self reporting may just be flawed. I believe that barring any of the above reasons for RE, a man who can't ejaculate inside a women is simply just not horny enough. Start there and you can then begin to discover the reasons for this. Deal with those reasons....everything from a preference for porn and masturbation to low self esteem and performance anxiety, and perhaps a course of treatment dealing with the causes of RE will lead to a cure.