What should I do

So my fiancé and I have been together for 2 and a half years this month and when we first got together I could talk dirty to him or send him pictures all day and he would get so turned on and tell me everything he wanted to do to me and all that good stuff...but now we don't have sex unless I start it let alone him sending me dirty things...it almost makes me feel unwanted sometimes....😥 and trust me I've tried talking to him and he fixes it for a few days then it's right back to where we were the week before...so what should I do?