Is it worse for a woman to cheat than a man?

The term "cheating" is way to ambiguous.

I can think of a dozen different ways my girlfriend could cheat on me, without ever doing anything sexual. Similarly, if I were to be gone for a month because of work, and she told me she slept with some guy one night because she was horny and I wasn't around, I could likely forgive that completely depending on the circumstances.