I too got the news that I had chlamydia. I couldn't believe he would do this to me. We have had anal sex, is it possible to get it from this. Or is it only through an infected person...

If the relationship is truly monogamous, no, but one partner here is infected, so it isn't a monogamous relationship, is it? Yes, you can get if from any type of sexual activity. Of course it is through an infected person, so you had better start asking questions, nor, get a partner you can trust.