Sex not so good anymore help!!!

So i have been with my fiance for about 8 years now he has been with me through thick and thin . when we first started dating i would get butterflies just thinking about him we finnally lost our v cards to eachother and had some bomb ass sex that made my knees go out from under me it was great fast forward a couple years later we still had great sex then about four years later it kind of got dull and boring always the same routine no excitement and im starting to loose that "flame" so ibegan to fake it worrying more about his needs and letting him finish leaving me unsatisfied so in desperation i began to watch porn trying to learn any new moves or try new things once he caught me and got really upset and when trying to explain myself he felt betrayed like he wasn't enough . don't get me wrong i still think my fiancee is attractive and handsome inside and out but how do i make our sex life better if everytime i talk to him about it or try new things it starts an argument and makes him feel worthless . i just want to go back to having that bomb ass sex cause i know hes capable of it 😖 its litterally tearing me apart helppppp!!!