D.,
What an interesting gal you are, thanks for the insight in the bio.
First of all, you are not wrong to want a break, you are the mother of four kids! Second of all, stop and think where those kids would be without you. You are really doing God's work, by loving, protecting and teaching those kids. That said, you need a break girlfriend.
You didn't say how old any of your kids were and that makes a difference. You need either a vacation or a hobby! If hubby is military, he probably spends more time gone than home. Mine flies and works 12 hour days easy. If you can't take a vacation alone, have some minivacations. We have date night EVERY WEEK. We get a sitter and go out WITHOUT THE KIDS. Doesn't have to be fancy or expensive, it just has to be every week and kidless.
You sound like a very independent and strong woman who enjoyed life pre-marriage/pre-kids. I am the same and although I love my three kids with a vengance, I also get burnt out and need some "me" time. I do Bunko once a month with the girls and every so often I am in a community theater play. We rehearse three times a week from 7-9 or 10. It gives me that little break and gives Daddy and kids some "bonding time." Look into taking a class or joining a team (art, cooking, cake decorating, bowling, soccer, basketweaving, whatever) at your local community center or sports facility. You will be happier to see all of the kids after having a break. In the meantime, shower all of the kids with love, and the two will have something to look forward too when they come back...also not bad idea to give a momento to each child so they can think of you when they are at Moms so they know how much you do love them! Good luck and God Bless you and your family!