you are in a hard spot op.
yes definitely get the diagnosis.
you can also take a short online test, that may give an indication. things to look for are risky behaviour, severe mood swings, shopaholic tendencies etc.
here is one:
[link to www.bipolar-lives.com]
there is no reason why your wife's employer needs to know, is there? as long as her work performance is not suffering.
it would be hard on the kids though. and you. and your wife. you both should go to counselling.