Losing once "Green Card" or lawful permanent resident status depends on the intent of the particular individual. From your description, it appears that your husband does not intend to abandon his status or relinquish permanent resident status in the United States. That being said, if your husband is absent from the United States for more than 1 year without a re-entry permit, Customs may questions his absence from the the US because a presumption of abandonment of lawful permanent resident status is triggered. However, this presumption can be rebutted given the factors you state above, such as, paying taxes, U.S. citizen spouse, house, bank account, etc.
To prevent this problem, your husband can simply file a re-entry permit if he knows that he will be out of the country from more than one year. If the company he is working for abroad, he may be eligible to preserve his ability to file for U.S. citizenship. This is not clear from the information you provided but perhaps something to explore.
DISCLAIMER: This is not intended for legal advise since more information and documentation is required to be able to advise on this matter.
I hope this was helpful. Good luck.