Do I tell my fiancée my ex text me he loves me?

My ex and I share a son.  We have been exes for 4 years.  The entire 4 years we never got along... Avoided eachother in every way.  Only spoke when needed and usually ended in him being hatefull to me.  I received a few texts over the past few months that say he misses me and he loves me.  I did respond to one in the past that it was inappropriate but mostly i didnt respond to them thinking he was drunk texting.  This past one I said it wasnt fair to my fiancee he be sending me texts like this but i know a few months from now I will receive another.  

My question is do i tell my fiancee?  It eats me up for a few days after i get the texts and dont tell my fiencee but then i dont feel as concerned to tell him once that passes.  If i tell him it may cause more stress between all us....