Do you think this should affect my marriage and should it be something I should be concerned about?

My husband and I have been together for 12 plus years, married 7. We have 2 children together and a fairly happy life. In the past I've had extreme extreme mother in law issues. It was mainly because he didn't step in and help solve them. He would allow his mom to walk all over me. That has changed and as a couple we have put our foot down. We distance ourselves from them, yet he still talks to his mom on the phone every once in a while. We see them for our kids bdays, holidays, and every now and then to be nice. Things have been great since we started keeping our distance. Anything she does or says doesn't bother me as much because I know that he's making it clear by his actions who his loyalties are with. My issue is with facebook. He refuses, outright refuses to go on facebook. His mother still spreads things to other family members about how unhappy he is, or she'll say he said something that I know he didn't say. I don't give her the satisfaction of fighting with her anymore or even really fighting iwth my husband anymore over it. We as a couple choose to ignore her and go on with our happy lives. Lately i notice most of my friends husbands are on fb and write nice and cute things to eachother back and forth. I don't expect my husband to be a huge cornball, but i would like it if he got on every once in a while and wrote how much he loved me or something nice and simple such as "I love you babe, you are great". The main reason why I want him to write this is because it will keep reinforcing to his mom and the rest of the family that we are happy and in love. And to make her look stupid when she makes up lies about our relationship. To make a long story short, my husband flat out refuses, and will NOT go on facebook to write anything to me. At first i thought he was just not into it, but now its starting to really bother me. I wind up thinking that for some reason he doesn't want the world to know that we are happy and in love. I just don't get it. Do you all think I should be concerned or do you think its just his personality to be private????