Maybe you should. Maybe it's just now starting to hit you. It might help if you knew why but be prepared, you might hear stuff you don't want to hear. If you do talk to them, get both sides. My parents divorced when I was 18 and had already moved out. Sometimes I wonder if it would have been better if they had ended it earlier. They should be expecting you to ask about it and be prepared. Whatever you do don't just keep it inside. Talk to someone about what's bothering you.
People should always be able to express their feelings. Something like that is important for you to let out and its also important that your parents know how you feel. If you don't feel comfortable talking to them directly at least talk to someone else about it.
you don't have to talk to your parents but try talking to some of your friends who have gone through the same thing. mine got divorced because my dad was on drugs. i have two friends who have gone through a sorta relative situation. or call love line with Dr. drew and psycho mike. they will know what to tell you.