It means 2 Christmases. No, I know this is serious business for you. Just keep on keepin man. Your mom and dad will still love you as much as they do now, and don't let this make you hate your mom. Yes what she did was bad, but lets face it everyone needs their mom.
I'm sorry this happened to you bro, but the older you get the less it'll bother you how your parents are doing. 5 years ago if you asked me how I would react if my parents divorced I'd probably cry cause I thought it meant something bad for me, or maybe it was my fault. Ask me now, and I'll tell you that if it makes both of my parents happier, then they should go for it.
Don't let this ruin your life.