There are so many good suggestions here! I just want to say that I am in a similar situation to yourself. My boyfriend whom I live with buys all kinds of junk food and he will eat it right in front of me. I don't ask him not to buy it, and I have to use self restraint to keep myself from eating it too. Sometimes it is too hard and I just give in. I highly recommend buying yourself something that you can eat when you just can't keep yourself from giving in.
(this is not when I'm on the HCG diet, because I can't eat anything even close to a potato chip on the diet) I buy goldfish crackers because they have a very large serving size for a lot lower calories than regular chips.
I also buy the quaker "quakes" I like the ranch and the sea salt and black pepper flavors. They are pretty low fat and I think they taste pretty good. My boyfriend will even eat them and he is VERY finicky.
Another suggestion you might try is instead of eating chips eat some green beans, garbonzo beans, or white kidney beans. I know that this is a poor substitution for chips, but trust me. Half a can and you feel full and don't want to eat chips anymore. But you should always have a low calorie substitute for yourself in case you have a weak moment. I hope some of this helps...