As someone whose parents are divorced recently, I sympathize with you on this issue. My opinion is that there is little you can really do in this situation and that their sadness (or lack of thereof) is mostly theirs to bear.
They are, however, very lucky to have such a caring child.
My recommendation (similar to
>>3,
>>4 and
>>5) is to do as best you can to remind them that you love them. Actions speak louder than word most often than not, but even leaving them messages from time to time could be nice, no matter which parent you choose to live with. Call them so that they'd know you care for their wellbeing, that you miss them.
I have no idea if you are a minor or not, but assuming you'll reach adulthood soon enough, I think it is important for you to know you need not feel guilty over your choice. Don't let yourself get guilt-tripped either. Rationalize your decision if it helps. I wish you good luck.