A straight scene (of any kind) would not, and does not make me stop reading a story. I think sometimes that it can even add to the story, but only if it fits.
There are a few stories, that I have enjoyed a great deal that had a few straight scenes. One that I am reading right now has quite a bit of 'straightness' in it, and I am still enjoying it. I am not reading these stories to 'get off.' A straight scene can be just s powerful as a gay one.
Think about it, when we watch TV, or movies, there are lots and lots of straight scenes. Do you turn the TV off if a guy and a girl kiss?
Kurt