Wife will not lose weight and take care of her body. I am losing my attraction to her, what should I do?

So my wife of 3 years has really let herself go after 2 kids. I love her, she is beautiful but she has a lot of extra weight in the belly area. I am beginning to find my self not attracted to her anymore. I spend a lot of time gone on frequent deployments so I cannot be home all the time to make sure she is eating and exercising to keep healthy. Am I wrong for wanting to leave her? Should I stay married to a woman I'm no longer attracted to for the rest of my life?? HELP