Possible Clues:

• Heart attacks expected at this time during month before march (2,9'1,3)
• Dean intends to be awkward in last romantic occasion
• The theme of this puzzle, which happened on Feb. 14
• Heart attacks expected at this time tomorrow (2,9'1,3)
• Proposal date, perhaps
• Heart attacks expected at this time during month before march (2,9¿1,3)
• In playful vein Sylvia sent date one, essentially to mark this?
• It's time to make love -- bonkers left at 22:16 hours (midweek)
• See 17-Across
• Romantic time