Husband out of danger? That's a nice surprise? (5)
I believe the answer is:
treat
'a nice surprise?' is the definition.
(I've seen this before)
'husband out of danger?' is the wordplay.
'husband' becomes 'h'.
'out of' indicates named letters should be taken away.
'danger?' becomes 'threat' (threat can mean a danger or risk).
'threat' with 'h' taken out is 'TREAT'.
'that's' is the link.
(Other definitions for treat that I've seen before include "Stand a drink" , "Celebration" , "Discuss" , "Pay for someone's food or entertainment" , "Entertain - minister - free entertainment" .)