It's interesting how over the course of a relationship, a person's character continues to unravel. You think you really know a person, but whether it has been one year or 20, there is always sides to a person that will surprise you (for better or for worse).
Of course, people naturally change over time—again, for better or worse—since that's part of growing up. However, I find it odd when two people have been in a romantic relationship for quite some time and yet, one of the partners grows unsatisfied to the point they feel they must alter the other's personality.
There is no such thing as the perfect relationship. It's inevitable that you will grow annoyed by at least a couple habits your significant other exhibits. Some people accept their partner's flaws while others openly try to adjust them.
Although you have every right to express your concerns to your partner, sometimes it's ideal to ask yourself, "Is this something that's a deal breaker?" In other words, is this habit so terrible it's relationship ending? If the answer is no, then why bother lecturing your partner and/or arguing, time and time again on something that isn't detrimental to the relationship? If the answer is yes, then let them know how you feel.
For example, if you require your partner to display affection then you should have an in-depth conversation about that necessity. However, if you're perfectly content with your partner's lack of attachment, then there's really no need in trying change this behavior because you're completely satisfied in your relationship. Not to say you shouldn't voice your opinion at all, but rather, approach the matter in a subtle manner instead of picking fights.
In many cases, it's so much more gratifying when your partner makes changes on their own accord. If a person changes because you asked them to, you're always going to ask yourself, "If I hadn't said anything, would they have ever improved on their own?"
It's quite common for people to want to fix something in their relationship that doesn't require fixing because desire clouds satisfaction. People say they accept their partner's imperfections; yet, continue to chastise them for their irritating habits. People that have been together for years should learn to accept each other for who they are as opposed to pointing out their character flaws on a regular basis.