Need Help! Sex drive?!

Need Help! Sex drive?

This is kinda emberasing but what are the causes of loss of sex drive. I am a married man of 7 years, in my late 20's and hardly have any sex drive. Me and my wife usally have sex about once a week (she initates) and I masterbate every 1 to 2 weeks. This is a far cry from when I was in my early 20's and even a year ago. We (me and my wife) used to go at it a min of 3 times a week and I would masterbate almost daily. What would cause this loss of drive. My wife is begining to think I don't love her or want her becuse I don't want sex very often.

A little information about my enviroment, I recently started a new job (6 mo) that comparied to my last job is very inactive, I sit most of the day and have gained a few pounds. My new job is also a little more streesful then my last job. My wife is also 6 mo pregnant (and still just as beautiful), but could the added stress of having another child be causing this. I believe it's related to the added stress but what do you have to say?

1. Go for a sensible diet n physical exercise to lose weight.
2. Stop masturbation when you think u r losing sex drive.
3. It's normal to have less interest in sex when u r stressed. Tell yourself, I will not think of tensions at my work-place when I am home. This will help.