sex and insecurities i may have or not?

ok i have a question or 2. ive been with my s/o for almost 4 years now. when we first had sex he was so amazing. he would last long time and we for sure would have sex more then 1 time in a day. now its like he lasts maybe 10 mins. and if i get it more then once in a day that would b awesome but now its like 1 time in a day maybe 2 or 3 times in a week. i feel he is not attracted to me its just a wham bam thank u ma'am.. and we been ttc since november 2017.. things just are not as they once were.. im very insecure about myself as well. i feel im not pretty enough for him or have the body he likes. should i b worried somethings going wrong or what??