"I thank your husband."
Translation:Ich danke deinem Mann.
No -- it depends on how many people there are and how well you know them.
You would use deinem if you are speaking to du (one person whom you know well).
You would use eurem if you are speaking to ihr (several people whom you know well).
You would use Ihrem (capitalised!) if you are speaking to Sie (one or more people whom you do not know well).
Of those three, eurem probably makes the least sense in this sentence, because at least in Germany, you can't have several people who are all married to the same husband.