Hi Welcome. I have gone through your query. I see that you are 28 years old and so the cause of ED in someone your age may be more psychological than physical (as opposed to someone with ED who is in their 60s). If you have no erectile dysfunction when you masturbate and only when attempting intercourse, then you may want to consider some behavioral techniques - which don t have side effects like the medications can. Behavioral techniques focus on decreasing performance anxiety and increasing intimacy. Also it is advisable to decrease masturbation to pornography (which creates unrealistic standards and immediate gratification) and avoid masturbation in general for a day or two prior to attempts at intercourse. For awhile, you may want to limit sexual activity to foreplay and mutual masturbation with your partner, to decrease performance anxiety. For further techniques, you may want to see a behavioral therapist who specializes in sexual dysfunctions. This provisional advice provided by me is based entirely on the input provided to me. I would suggest examination by the doctor. I hope this suggestion might be of some help to you. Take care.