@dag444gad the requirement is to have contributed more than half of household expenses for maintaining a household for the children -- not the actual income.
On the other hand if you are going to file joint then consider excluding both your incomes from US taxes -- each must file form 2555.
I don't know which country you are in but it is strongly suggested that (a) you read up on the tax treaty between US and that country and (b) perhaps visit the nearest US Consulate -- they often will have an IRS section that can advise you
Is there more I can do for you ?
