How do you get your wife to care about her own appearance?

It looks like there's something about motherhood that changes everything. Our first child is four years now and the second is almost three years. My wife's sister lives with us now and helps take care of the children and also does almost everything in the house. I'm four years older than her but she looks like my senior sister. She cared about her appearance and what others thought about the way she looked. Those days, she didn't have to ask me about the way she looked. Immediately she's done dressing, I will tell her, "You look beautiful." Then she'll respond, "You don't have to tell me. Beauty is in my blood." Nowadays, she'll put on just anything to cover her nakedness. Maybe she's not proud of herself when she looks in the mirror so she'll avoid the mirror and instead come and ask me, "Nii, how do I look?". I'm not saying all these to look for an excuse to cheat or be with someone else, no. She doesn't care that we don't do it like we used to. She had stopped caring about everything she once paid attention to and recently I asked myself the question I never thought I would ask myself, "Should I walk away?". One night I decided to pick a harmless fight with her and use the opportunity to look into her eyes and talk about things. In the morning I asked, "So you chose sleeping on the couch over brushing your teeth? Your own teeth?" She answered, "Like you rightly said, It's my own teeth plus I was feeling sleepy.” What should a man do to get his woman to care about her own self and care about the health of their marriage? Maybe I'm being superficial. You look at it, it's a problem to me and I wish she could do something about it. Source | Summary