How do you know she’s not depressed? You indicate she hasn’t been to counselor, a therapist, a psychiatrist. She may very well be depressed, many depressives don’t appear to be and don’t even suspect they are depressed.
How do you stop loving someone? In my world/mental view you don’t. Love is a choice under your control, it’s why you can take a vow to love someone, it’s why Christ said to love even our enemies. Love is an action we take, a decision we make. As a priest said though, Christ commanded us to love people, he didn’t say we had to like them.
My now legally ex-wife believed love is a feeling. Something beyond her control. Unfortunately, depression isn’t sadness— it’s a lack of feeling. In that paradigm you stop loving someone by losing feelings, depression being a cause. Problem is, if you can lose that feeling for a spouse, if love and feelings are beyond your control, than you can just as easily lose that feeling or connection with your children, or your parents.
You assume your wife may stick around for the children. She is just as likely in today’s world to want to get away from them, even more so than you. She may not want to admit that to herself. She may in fact be turning you/your relationship into the excuse she needs to leave the marriage or force you to make that decision. I don’t know her/you well enough to know if she’ll also be driven to distance herself from her kids. Lot’s of men in my position-- I have my children living with me full time. All driven by choices she made, not me. I didn’t have to fight for my children, simply allowed (ETA: while advising against) her to follow the course of action she chose whose logical and obvious outcome would be the situation as it stands now.
What you can do? Pray, read up on depression-- good place to start
www.depressionfallout.org and the book “Depression Fallout”. See if your wife’s words/actions match, keep listening to your wife, keeep talking, try and find activities you can do together, encourage her to consider going to counseling/marriage encounter/retrovaille. Plan a strategy to have full custody of your kids if you end up getting separated/divorced.