It Must Have Been The Mistletoe

Description for IT MUST HAVE BEEN THE MISTLETOE by Moyra Tarling:

Seven Years Ago, Mitch Had Sought Comfort In Abby's Arms Mitch thought they'd found something special that night, something lasting; a perfect love. But believing Abby had betrayed him, he'd left, vowing never to make that same mistake again....

Her Love Had Been Abby's Only Excuse She'd learned a painful lesson when he'd vanished from her life. Now the holidays had brought him back--forcing Abby to reveal her secret--their son--at the risk of losing Mitch again.

Silhouette Romance #1122, December, 1995.