Set apart from one's love, in arrears (7)
I believe the answer is:
Here is my best explanation:
'set apart' is the definition.
('isolate' can be a synonym of 'set apart')
'one's love in arrears' is the wordplay.
'one's' becomes 'is' (Roman numeral).
'love' becomes 'o' (In tennis, 'love' means 'zero').
'in arrears' becomes 'late' ('late' can be similar in meaning to 'in arrears').
'from' is the link.
(Other definitions for isolate that I've seen before include "Cut off from all contact", "exile?", "Point out", "Ostracise", "Place or set apart", "strand", "Pick out", "Segregate or quarantine", "Eat soil (anag)" and "Place apart, away from others".)