Question: I really get turned on by my wife,,but after foreplay withher i lose my erection

Perhaps you are experiencing some kind of stress in your life, and when it comes time for penetration you become nervous? Erections are controlled significantly by psychological issues. Even if you are just slightly off your game in your head it can have serious reprocussions for your penis. It sounds like to me you are sexually attracted to your wife but there is some sort of pressure in the back of your mind which causes this loss of erection. Work with her on this and explain the situation. Talking about it may help.