Be prepared
I have had 2 together for the last 6 years & they are wonderful together!
They play, and keep each other company when we are not around, and sometimes act just a husband/wife combo (yes with the ocassional squabbles)
Since both of mine are fixed, I made the move purely for them and their happiness.
Now what I always tell people is that this is not "simple math". In this case, 1+1 = 3. 2 Boxers (or any dog) take much more time for many tasks (feeding & bathing is sometimes easier), so be prepared
Good luck on your decision!