The 26-year-old singer is on a world tour while Russell is making movies in America, and a source told the Daily Star that she is doing everything that she can to make things work.
'Despite working her butt off on tour, Katy's really making a huge effort to ensure she sees him as much as possible – even if it means she's basically living on planes,' the insider said.
'They said they would never go over a week without seeing each other as part of their 'marriage rules'.
'But with her world tour and his filming it's proving difficult.
'It'll depend on how solid they are as a couple whether they get through this tricky time.'