My parents split when I was 11. My mum left, she'd been cheating on my Dad for 6 months. I was fine. I just didn't speak to my Mum for 2 years, not because she left or because I was upset but because she lied and she cheated, which was bang out of order. I forgave after about 2 years and we started getting on again.
If it's going to make both of your parents happy in the long run then I wouldn't worry about it too much,just concentrate on your studies.
Edit - Just realised your from Bish, me too. Getting away from that place in September will do you the world of good, trust me. Focus on getting yourself to uni.