1. Never say what you mean, or mean what you say. Insincerety is a great way to ruin a relationship.
2. Hoard the chocolate ice cream. Never divulge its hiding place, and always let your significant other see you eating the last of it.
3. Play guessing games constantly. Never let your SO know what you really want or think. Enjoy watching them squirm as they attempt to read your thoughts.
4. Steal the covers at every opportunity. Bonus points for perpetually cold feet.
5. Never, ever, under any circumstances make any committment whatsoever. Flee the room in hysterics if the subject of the future comes up. Absolutely refuse to discuss anything beyond the day after tomorrow.
6. Dodge your SO's phone calls. Don't bother to disguise the fact that you're dodging their calls. Bonus points for talking in apparent code phrases to an opposite-sex friend over the phone while in the presence of your SO, then innocently assert that you're just good friends with the other one and that "there's nothing to it".
7. Whine constantly. About everything. Whine about the fact that you're whining.
8. Insist upon controlling every aspect of your SO's life. Exclude their family from everything. Firmly plant yourself between your SO and their parents and siblings.
9. Talk constantly about how you're such good friends with all of your ex-SOs. Especially if you have children with one or more of them. Bonus points for comparing physical and personality traits of your current SO with any one of your ex-SOs.
10. When you have the choice, go hang out with your friends over your S.O. Bonus points when you can use your S.O. as your babysitter for your kids while you are having a great time with your buddies