There are sooo many things that users do to bypass the rules (not saying that your husband was), that Swagbucks has really been cracking down on things the past few months. A lot of people have gotten the accounts deactivated when they weren't violating TOS and the reoccurring theme seems to be that it was people in the same house, oftentimes when one had referred the other that one of the accounts is deactivated. Even though there is nothing in the TOS that states you can't have more than one account per household, it seems they are quick to assume that those accounts are being used by the same person (which would be a violation), even if they are actually being used by separate people. If both of you are logged into Swagbucks at the same time, whether it be on the same device, different browser, or completely different devices, and both watching videos, if you are under the same IP address, it will likely flag it in their system that multiple videos are being watched at the same time from the same IP address. In this case, you likely wouldn't receive any warning and everything would credit since you are actually using two separate accounts, but most likely in their system it just pops up that multiple videos were being accessed under the same IP address at the same time and they assume the same person is watching them. If you are using the same device and different browsers, the IP address would be the same. For different devices, the IP address may change if you are using different internet connections (ie one under your home's wifi and the other under your phone's data plan or someone else's wifi).
If it's possible that you and your husband were both running videos in separate accounts at the same time and Swagbucks gives him trouble reactivating his account, I would recommend sending a reply email explaining that there are two different accounts in the house that share the same internet connection, but you are two separate people. I have seen posted on reddit about people having this issue and after explaining it to Swagbucks (and sometimes offering some sort of proof that they are separate people, such as copies of licenses showing name and address), they have had luck getting their accounts reactivated.
This may not be what your particular issue is, but in case it helps, I just thought I'd share.