Treacherous type losing wife's support (5)
I believe the answer is:
easel
'support' is the definition.
(easel is a kind of support)
'treacherous type losing wife's' is the wordplay.
'treacherous type' becomes 'weasel' (I've seen this before).
'losing' indicates named letters should be taken away.
'wife' becomes 'w'.
'weasel' with 'w' taken out is 'EASEL'.
(Other definitions for easel that I've seen before include "Stand used by artists" , "Supporter for the artist" , "The rest of artists" , "the rest of the paintwork" , "Lease (anag)" .)