Gavin Rossdale has found himself at the center of rumors claiming he had an affair during his marriage to Gwen Stefani. The couple split in August after 13 years of marriage with seemingly no explanation as to why they decided to go their separate ways. New reports suggest Rossdale, 50, may have been unfaithful -- but with who?

According to Us Weekly, the musician may have been cheating on his wife with Mindy Mann, the nanny hired to care for his three sons. The publication reports the affair lasted three years, noting that Mann began taking on behaviors and style tidbits from Stefani, 46. The former No Doubt front woman is said to have noticed Mann's strange copycat behavior and "thought it was weird." E! Online reported on several instances of Mann stealing Stefani's signature style in the last few months. For instance, in June the mother-of-three stepped out sporting an army green jumpsuit. The same month her nanny was seen wearing a strikingly similar jumpsuit with her hair styled exactly the same way.

Stefani reportedly found out about the affair in February after uncovering suggestive texts between Rossdale and Mann. In the exchange there is said to have been a nude photo of the family nanny along with plans to meet for a sexual encounter. Another nanny reportedly saw the texts and brought them to Stefani's attention.

"The iPad was linked to Gavin's phone," a family source told Us. "One of the other nannies discovered the exchange and told Gwen."

Shortly after Rossdale and Stefani split it was rumored that she and Blake Shelton, with whom she co-hosts NBC's "The Voice," were dating. On Nov. 4, the same night as the Country Music Association Awards, stories began cropping up claiming a rep for Shelton, 39, confirmed that the pair were dating. The "Sangria" star's ex is said to have become suspicious about her ex-husband's relationship shortly after it was confirmed. She met with Rossdale to discuss her suspicions, saying she felt it was "strange" that the nanny cheating scandal would break now rather than when it allegedly happened.

Stefani has since denied dating Shelton. During an interview with the "Frankie and Geena Morning Show" on San Diego's channel 93.3 she was asked about her “new relationship” at which time she told the host she found his inquiry to be rather personal, before stating that she “never said” she was dating anyone. Stefani claimed she didn’t know who supposedly confirmed their relationship, but it wasn’t her. In fact, “The Voice” host revealed that she learned about the rumors from one of her sons.