His ex has control over him and I’m nothing!

hi,iv bin dating dis guy 4 almst 4yrs nd has 2 kids wit his ex,de prblm is wheneva sumthng cum up nd happens dt he talk abwt his ex,if i comment or ask sumthing abwt de ex is lyk im offending him.meanwhile he is free 2 do so wheneva,i feel lyk he is shutting up evn whn it cums 2 his kids,if i suggest sumthing he doesnt take it serious.de baby mama dsnt want him 2 c de kids outside her home,xes olwys der wheneva he want 2 c de kids,nd says im overreacting whn i say he xuld take dam sumwhr.its lyk de ex has a control over him nd im nothing.he is shutting me out nd 2mrw deyl say i dnt love his kids coz im trying ol my best dt we go out 2geda bt he prefers 2 be at de ex home i gues.wt must i do?cn u pls reply via email