My girlfriend has to keep peeing during sex. Major kill-joy. What do I do?

We're aware of "squirting" and I keep telling her that she isn't going to pee she's going to squirt and she still insists on going to the bathroom and within the amount of time she's gone I'm no longer interested. But the real issue is that she goes pee before foreplay and by the time I get up to go get the condom she leaves to pee claiming she has to pee and then she returns saying she took a while to pee. It really bugs me because what she does is a major turn-off and it would be nice to know how to handle the situation.