Girls, Is this a sign she would cheat?

So basically i sometimes notice that my girlfriend will see other men check her out and they will exchange glances and clearly be looking at each other through out the evening. I've noticed this a few times. It has made me feel uncomfortable at times and i have tried to bring it up but she flat out denies it and i dont want to make a mountain out of a mole hill. what does this mean? Whats should i do? any advise would be appriciated.

Girls, Is this a sign she would cheat?
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