Hi @Maira45,
The only possibility to sync 2 accounts together is when one of them is business one and the other is personal. In such situation there is option to link both accounts so they can sync together.
Otherwise, you can still sync different accounts on the same device, but you need to run different local profiles for each Dropbox account. On a single local profile may runs single Dropbox account only. So, if you and your husband have independent local user profiles you can use both of your Dropbox accounts on matching local profiles without mixing them (not locally, at least). 😉
Hope this helps.