Shouldn't someone have questioned why a married man with a child was being sent there for such extended periods, it's not like they didn't know he had a family?
Dee, I'm not unsympathetic to your feelings, but ...well, you're blaming the wrong people.

Married men with families get sent all over the place all the time for work. I'm not going to see my husband for the next three days, he's off on business.

Does his company know he has a family? Yup. I'm friends with his boss. I've met the boss' boss. They know I'm chronically ill and that we've got two kids.

They also know that he's got a job to do. It's what they pay him for, and they owe me no explanations.

Your husband is a grown-up, and it's incumbent upon him to act like one. It's not his employer's responsibility to babysit him, nor is it their responsibility to report his every move back to you.

Lay the blame where it belongs - squarely with him.

Best of luck.