I get tired of eating the same thing over and over. I was prepping the veggies for my veggie omelet last night and I thought, dammit, if I have to eat one more omelet with mushrooms and zucchini for breakfast, I might kill someone. So I had cereal with yogurt and berries instead. Yum!
There are tons of ways to eat healthily, and the nice thing is that mother nature encourages dietary diversity. You spend a couple of weeks eating nothing but asparagus and finally, when you get to the point that you can't bear it any more, something else is available and delicious. Ditto pineapple, peaches, tomatoes or whatever else.
Wanting variety in your diet should have NO IMPACT on your 'diet'. It's perfectly natural. Just think of new and delicious things to make.
(I am, however, jealous of my boyfriend, who can happily eat the same damn spinach salad with chicken for lunch, day in, day out. I can't do it.)