Losing Errection during penetration sex

Hi I am 27 year guys, having very slim body,
I am addicted to masturbation and and almost masturbating on daily basis, some twice or thrice on day.is this a problem

also facing a problem from some time.i am losing my erection during penetration sex.me n my girlfriend tried it few times but got failed.
during foreplay i am getting good n hard erection on almost 8 inches.

Is this physical or mental problem

[palpateit]

Have you been using porn consistently for masturbation? If so that is the main cause of ED in men under 40. The inability to get excited by a real-life sexual partner, or losing and erection is very common - it is called copulatory impotence. On our recovery forums, we have men in their teens with porn-induced ED.

Over the last 5 years we have seen hundreds of men on our porn recovery forums with ED. Many in their teens and twenties. They stop porn - and limit masturbation - and they slowly recover their libido and erectile health. Most health professionals are unaware of this rapidly developing problem. They don't understand the neurobiology of erections in relation to overstimulation by porn.

Check out this thread. Read the posts. "Control find" palpateit and read my first few posts and follow the links to the video presentations on ED and porn.
http://www.medhelp.org/posts/Mens-Health/22-with-porn-induced-erectile-dysfunction/show/469209

Science is starting catch up - here's research from a month ago -

SCIENTISTS: TOO MUCH INTERNET PORN MAY CAUSE IMPOTENCE (2011)
It may not make you go blind, but Italian scientists have identified a worrying side-effect of watching too much pornography.

Researchers said Thursday that young men who indulge in "excessive consumption" of Internet porn gradually become immune to explicit images, the ANSA news agency reported.
Over time, this can lead to a loss of libido, impotence and a notion of sex that is totally divorced from real-life relations.

"It starts with lower reactions to porn sites, then there is a general drop in libido and in the end it becomes impossible to get an erection," said Carlo Foresta, head of the Italian Society of Andrology and Sexual Medicine (SIAM).

His team drew their conclusions from a survey of 28,000 Italian men which revealed that many became hooked on porn as early as 14, exhibiting symptoms of so-called "sexual anorexia" by the time they reached their mid-twenties.

There was some good news, however, as the condition was not necessarily permanent. "With proper assistance recovery is possible within a few months," Foresta said.

Other data presented at the SIAM'S annual conference in Rome suggested that Germans are the biggest consumers of online porn in Europe, with 34.5 percent of internet users logging on to watch smut.
France ranked second (33.6 percent), ahead of Spain (32.4 percent) and Italy (28.9 percent)