Ten minutes for self-care isn't too much to ask. You need to be selfish for just a few minutes each day, even if it's just ten minutes. Have a coffee on the back porch, listen to a favorite song, or peruse an insightful internet blog. You'll be a stronger person for it.
Take control of your life by working around your family schedule when you can. Take an occasional early day to pick up your kids at school. Visit an ice cream shop for a special treat. Your kids will remember you being there for them.
Eat a candy bar! Skip your workout! Tell your kids you need to use the bathroom, and read a magazine instead (peace and quiet!!). Just don't do it too often. It can be habit forming!
Sometimes putting what we feel on paper helps us get through it. Write a letter to yourself (or to someone no longer here!). Say how you feel. Let the tears fall. Then close it up and stick it on a shelf. You can open and reread it anytime. You'll find your feelings are easier to bear each time.
Or any other day of the week, but eat at your favorite restaurant occasionally. Alone or with someone else, just do it! You'll enjoy the experience and get a full tummy, too!