Spoilt

For those who, like me, are considering not voting or spoiling their paper in the forthcoming election: Not Apathetic.
I’m under some pressure from my wife to "vote properly". I can understand her reasons for this, and feel strongly that I have a moral responsibility to attend the polling station. But without a "none of the above" option, is it right that I should put my vote against a party or candidate whose policies I do not support?