Who actually paid the disability pay? Your employer or the insurance company?
Whomever is supposed to, report that W-2 correctly on your taxes. Ask the other entity for a corrected W-2. If they provide it to you, then report their corrected W-2 on your taxes and everything should be OK. If they refuse to correct it, follow whatever the IRS procedure is for when an employer refuses to correct a W-2.
And yes, if your W-2 totals don't match what the IRS received with your SSNs on it, then it'll probably trigger an automatic correction letter and you'd be expected to pay taxes on the incorrect higher amount.
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Another possibility is that you are mistaken and your wife's disability pay was not included in her employer's W-2. Carefully compare her pay stubs or direct deposits with the totals on the W-2 to figure this out.