毕竟不分手的恋爱只是首歌
[bì jìng bù fēn shŏu de liàn ài zhĭ shì shŏu gē]
Translates to 'After all, a love that never breaks up is just a song'. It implies that perfect relationships are often romanticized or idealized but hard to achieve in reality, similar to how songs depict perfect love.