I also have two dogs (two cats, two birds, mts and insanity!)
Its the whole pack leader thing here.
I woud suggest going to Dog Training Classes (I go every Thursday and it has made a massive difference)
Some top tips,
- never ever let the dogs pass a boundary, typically a doorway or gate before you or without your permission, in the dog world the leader always goes first
- always eat before your dogs and keep them at least 3 foot away from you while your eating, then feed them after, do not put their food down unless they are calm; in the dog world the leaders of the pack eat first and get the best bits of the kill, then subordinates are allowed
- when you return home, or even from another room, ignore the dogs for a few minutes (even though it may be the best welcome in the world); when they calm down give them 2 seconds of attention and wait till later before any serious attention from you; in the dog world the pack leaders ignore subordinate dogs when the pack returns to the den after hunting
- do not allow your dogs on furniture, especially beds, the sofa; in the dog world the pack leaders rest and sleep at the heart of the den, subordinates are not allowed near
The reason you can stop the dogs fighting is probably not your strength, it likely to be that the dogs see you higher up the hierarchy than your wife; this is typical in a household where there are male dogs, castration may calm them a little but it won't solve the root cause which I suspect to be pack hierarchy issues. In any case, I would castrate; but that's more of an opinion than a fact.
My guess is, as stated, they are fighting for pack dominance, I would really encourage you to attend classes.
If one is allowed to establish dominance the other dog may be badly hurt in the process. Then, the attentions may turn to other pack members seen as a threat, i.e. intruders to the house (visitors, kids) or even you and your wife; more likely your wife.
I watch Cesar Milan all the time on Sky Three; I learn something new every single episode.
21G: ADFs, Amano, Cherry and Tiger Shrimp
50G: Pearl Gouramis, Guppies, Neons, Lemons, Pygmy Cories, Otos, Clown Plec, bristlenose pleco, platies, swords
50G: Tall, bowfront SA setup, Angels, Festivums, Rams, Pictus', Raphael, bristlenose pleco
(10g QT tank)
80g: Mbuna, Red Zebras, Yellow Labs, Blue Cobalts, Lab Hongis, Bumblebees, Syno M.punctatus, Plec