Kevin, who was rumoured to be reuniting with estranged wife Britney Spears, has no idea his on/off lover Shar Jackson (right) is expecting their third child. A source told America's Star magazine: "Shar wants to tell Kevin, but she keeps getting cold feet! She's really scared of what he'll say - if he'll be excited or furious."What if he doesn't want another kid?'"After all with her two children , and Britney's two, he's got his hands full already! It would be Shar's dream for them to get married and have another baby. She'd love to be living the family life with Kevin."Shar - who has a four-year-old daughter, Kori, and two-year-old son Kaleb with Kevin - is said to be seven weeks pregnant.She is reportedly convinced the baby is his because she hasn't been with anyone else. Kevin also has two sons with Britney, 21-month-old Sean Preston and nine-month-old Jayden James. Britney is allegedly desperate to patch things up with Kevin and used her recent New Mexico break to mull over their relationship. A source said: "When she was on vacation she was in the best mood she's been in for ages. She confessed it was because she and Kevin are slowly moving towards getting back together."Britney, 26, and Kevin, 28, are said to be having secret meetings and long heart-to-heart telephone conversations.