Undecided about husband being a source of irritation (5)
I believe the answer is:
thorn
'a source of irritation' is the definition.
(I've seen this before)
'undecided about husband' is the wordplay.
'undecided' becomes 'torn' (someone deliberating between two options is torn).
'about' is an insertion indicator.
'husband' becomes 'h'.
'torn' going around 'h' is 'THORN'.
'being' is the link.
(Other definitions for thorn that I've seen before include "Plant spine; old letter" , "It causes irritation and annoyance" , "Spine on some plants" , "tip of R [ROSE]" , "Feature of rose tree" .)