Katy and Rob decided to part ways because she felt their respective work commitments gave less time to spend with each other.
The main reason she split with Russell was because she ended up spending much of her time on tour. "She said dating Rob felt like being with Russell all over again," showbizspy.com quoted a source as saying.
"It's a shame as they both liked each other but Katy wants to be able to have a relationship with someone she isn't constantly having to work out what time zone they're in," the source added.
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