Part of the problem could be the natural aging process...has this issue been there your whole life or just recently? Often times sexual problems relate to anxiety about the sex or some stress in the relationship. Who are you having sex with these days?
You can discuss with your doctor whether medications like viagra are an option for you. You can also see a therapist to discuss the problem in more detail and find specific solutions.
Here is a book that can help too: Overcoming Impotence: A Leading Urologist Tells You Everything You Need to Know by J. XXXXX XXXXX. You can also check your local library or bookstore for other similar books.
Let me know if I can answer any other questions. Take care & good luck.
Okay, that is helpful information. I bet deep down you are a bit insecure and or guilty about having sex with women since your wife. Psychological issues cause sexual problems more commonly than physical. The fact that you can masturbate ok is evidence of that this is likely the case for you.
Although a sex therapist would be great, you could also see a regular therapist. I would definitely read some books on impotence (or erectile dysfunction or male sexuality; maybe even one of Dr. Ruth's books on sex like Dr. Ruth's Sex After 50: Revving up the Romance, Passion & Excitement! (The Best Half of Life) by Dr. Ruth K. Westheimer. The combination of reading some books and seeing a therapist is highly likely to help you overcome this issue. Let me know if you have other questions.