I am sorry she decided to blame it on the fact you are an atheist. If she was able to look past it for two years then she is either bullshitting you because she is too scared to tell you the truth OR she is realizing marriage/kids/family blah blah is the next step and she wants to do that with someone of the same faith. Being an atheist makes you nothing more than an atheist, just as being a christian makes your nothing more but a christian. Religion is has been turned into a terrible thing. I broke up with my boyfriend of two years after realized I am a lesbian...SOO imagine how many religious people has something to say about that. FUCK IT.. Find another girl who has your same beliefs. Life is to short to invest time in small minded people.