Question2009,
First off, let me say that masturbation is a totally normal and natural method of stress relief. I myself, masturbate at least once daily as a means of pleasure and stress release. Now to your questions...

"I'm 37,single male and under a massive amount of pressure in business 9 I know, no more than anyone else) and have over the last circa 5 months started to masturbate every day, literally."

There is nothing wrong with this, masturbation is normal.

"Some days it may be twice but that would be 2 out of 7 days. Obviously its the entirely incorrect way of dealing with stress and the gym would be better."

Okay, so 2 points here: Masturbation is a great stress release mechanism; Doing physical activity such as sports or the gym is another stress release mechanism.

"Is it possible to become �ddicted' to matsturbating?"

I'm not sure about being addicted to masturbation or simply becoming too self absorbed and using masturbation as your prime or single source of sexual release.

"Is it harmful in a medical sense i.e. can it lead to fertility problems?"

I have never heard of masturbation causing infertility. Fertility problems usually have other reasons for occuring.

I realize that this is a sensitive topic for you and I hope that I have been able to provide some helpful advice. If you would like to discuss further or in detail, please feel free to private message me if this will make the process easier for you. I am very open on such topics and will tell it as I know it.

Wendy