His wife just had a baby. His mistress is next

DEAR ABBY: My sister has been seeing a married man for two years. He has told her the only reason he is staying in his loveless marriage is for his daughter (standard lie of a cheating husband).

His wife found out midway through this "relationship," but forgave him when he swore he would stop, which of course he didn't. When I told my sister how wrong this relationship is and that she deserves better, I ended up alienating her.

I have recently learned that his wife just had a second child, and my sister is pregnant, too. I'm sick to my stomach with all of this. I told her how crazy her situation is, but she refuses to see how horrible "the man she loves" really is. She says she is fine raising this child alone, and if her lover is in their lives, then she will be satisfied with that.

I am the only one freaking out about this. How do I deal with it and not totally lose my sister?

- Freaking Out in Illinois

DEAR FREAKING OUT: Your sister is an adult. She has made her choices and may have to learn the hard way what you have been trying to tell her. Realize that as much as you love her, you cannot live her life for her. Let her know you're there for her and the baby, because she's going to need all the support she can get.

DEAR ABBY: I am 30 and my husband, "Brent," is 35. We recently had to move in with my mother-in-law.

My question is: How old should a child be before his mother quits walking around naked in front of him? My mother-in-law still walks around completely nude in front of Brent and his 39-year-old brother. She also parades nude in front of me.

Is this normal behavior? Am I overreacting?

- Covered Up in the Midwest

DEAR COVERED UP: Because her nudity makes you uncomfortable, the most tactful way to approach this would be for Brent to explain to his mother that you were not raised this way, and that you both would appreciate it if she'd wear a robe when you're around. It's worth a try.