Dogs fight each other

Question
I have 3 dogs.  A 4 year old female Mini Schnauzer, a 3 year old Mini Schnauzer and a 2 year old Boxer.  They are all fixed and truly get along well.  They never fight over food or toys and are fine during the day.  The reason I say during the day like that is because I work from home and my wife works outside of the house.  When my wife gets home she caters to the dogs.  They all cuddle around her and she's ok with that.  What will happen sometimes is the female Schnauzer and the Boxer will stare at each other and before we know it they are going after each other.  They never bite each other but jump at each other.  What could be causing this behavior.  Any info would be helpful because truthfully, I'm over dealing with it!  Thank you.

Answer
Could be some protective issues between the two dogs; both may be competing with each other for the attention of your wife.

You mention that the two dogs will stare at each other before the ruckus.  That may be your clue that something is about to happen, and that's the time when you need to re-direct the dogs or separate them.  Your wife needs to be attuned to this as well since she's the apparent "cause."

I assume you know the difference between dog rough-housing and actual conflict?  Sometimes when dogs play, they sound as if they're killing each other but nobody actually gets hurt.  This isn't what's going on, is it?

Your wife may want to reconsider what kind of leadership role she wants to assume with the dogs.  "Catering" to them gives dogs the impression that the human is to serve the whims and needs of the dog.

Here are some hand-outs that may be helpful:
http://www.marinhumanesociety.org/Behavior/Handouts/PEP.pdf
http://www.ddfl.org/behavior/nilif.pdf
http://www.ddfl.org/behavior/educated-dog.pdf