More than anything this is just an issue with your mind that can easily be tackled. Its your mind that turns you on and gives you an erection. And it is the same mind that makes you favor your own hand over your wife's company.

Seems obvious you aren't enjoying sex with your partner.

Orgasms attained through masturbation are quicker compared to the ones got while having real sex. Possibilities are high that you are expecting the same while having sex with your wife, too.And the disappointment of not having a quick one is making you lose your interest and in turn your erection.

To lessen the appeal over masturbating.. you must start having G-R-E-A-T sex. And to have great sex , you must be in greater relationship with your Lady love. You know, talking is the key here. You need to involve her and at the same time get involved. Talk to your wife about your sexual fantasies and if she is unaware, introduce her to giving you some kinky oral sex. This might turn out lot more fun and pleasure you doubly than helping yourself .

Next time you have sex, try to gather what it is that which is putting you off ; Once you find out what it is, your problem is half solved. Also, stop doing any strenuous activity before having sex- it might tire you.

NOTHING HAPPEN, IF YOU MASTURBATE TWICE A DAY, MORE IMPORTANCE DON'T THINK AFTER MASTURBATE. FUCK IT FORGET IT