(nowmagazine.co.uk ) - Avril Lavigne has spoken out about rumours her marriage to rock singer Deryck Whibley is on the rocks. US reports claimed the couple were drifting apart due to work commitments.But Avril, 24, insists they're very happy together.'We're best friends,' she tells In Touch. 'We have so much in common and get along all of the time. He makes me happy.'Sum 41 frontman Deryck, 28, flew out to Asia earlier this year to support her on tour.'Deryck joined her for 2 months,' a friend says. 'He performed on stage with her every night and they sang her hit In Too Deep together.'The couple - who wed 2 years ago - have been together for 4 years.