My boyfriend was diagnosed with chlamydia and my results came back negative. we have been together for 7 months. does that mean he has been unfaithful?

Not necessarily: It's quite common for only one member of a couple to test positive for chlamydia. Often it means the infected partner has been unfaithful, but not always. The test misses some infection. You may have had it, but your immune system cleared it up. The important thing is for you to be treated, even with your negative test result. And have an honest, frank discussion with your boyfriend. Good luck.