Every woman sometimes does. Honestly, unless it's often, it isn't a problem. Your boyfriend may also just be uninformed, or maybe he just doesn't like the way a woman smells and wants to blame it on you. That place will have a smell, no matter what you do. But so does the rest of your body. Tampering with your vagina means tampering with it's ability to regulate the bacteria that live in it, and it's ability to clean itself. Eating healthy is a good idea, more drastic measures not so much.
Wash with unscented, fragrance/dye free gentle soap, wear cotton underwear, don't douche, and drink more water than you think you need to (a gallon a day is good). Eat fresh fruits and vegetables, doesn't matter what kind as long as there's variety but do make sure to wash them first before eating them, with dish soap or vegetable soap. Avoid MSG, preservatives, pre-packaged foods (especially frozen meals). Eat foods containing probiotics, or take a probiotics supplement (good, expensive yogurts will work for this). Eat less in general, avoid anything with refined sugar and limit raw sugars too. That should be enough to ensure good health, and clean smells.
You can go further: limit your meat intake to not every day and use vegetable proteins on the non-meat days. Or go all vegetarian. Better yet, go all vegan. Even better yet, switch to a raw foods diet!!! It all depends on how far you're willing to go in search of ultimate health, honestly.