forclosure on one house but not both

If I have a mortgage in my name but both my husband and my name are on the deed, is he as responsible for the debt as I am?
If my husband invests into another property, in his name but both of us are on the deed, is his investment at jeopardy if I default on the loan that is in my name and foreclose ?

Normally the one that signed the loan documents is responsible unless you are in a community property state and signed after you were married.

As a practical matter, most lenders these days always try to have both spouses sign for any loan on a home.

By the way some loan documents permit cross default--ie default on one and you default on theirs. So check your docs closely.