The 50-year-old singer-guitarist is "suspicious" of the timing of his and Gwen's split and Blake and Miranda Lambert's divorce which are less than just a month apart, reported TMZ.
According to the sources, Gwen kept her affair with Blake a secret because she's worried he would fight for more money in the divorce if he knew she cheated on him.
Gwen and Gavin announced their split in August this year, and reached divorce settlement in October.
On November 4, reps for Gwen and Blake confirmed that "The Voice" coaches are dating.