Is she cheating on me?

to me it seems like maybe your not giving her enough love.after being together for so long love starts to die.everything is a routine and 'i love yous' are sounding so original.not having any meaning anymore.maybe she didnt want you to see the poem becuse it is about you.does she act like she loves you alot still?maybe she needs more attention.or something new in the relationship.And if she is cheating..just confront her about the poem.ask what or who its about.