sexting with my boyfriend but he said something that got me emotional 😔

So my boyfriend and I known each other since freshman in high school and we were on and off during high school . Senior year came and we stopped talking ,after we graduate (2014) 2 years passed by and we started talking again and made it official January 1, 2017 . 3 months passed by and we started having sex ! In my point of view I think our sex is mind blowing!!! He actually pays attention to me during sex , he makes me cum(first guy to ever make me cum)  , and his dick and balls are amazing!! Everything is perfect lol  I read those stories on here sayin " my husband/boyfriend sex is mind blowing" ,that I finally understand how it feels lol  anyways I'm PMSing rn ! I was really horny a few mins ago so I was sexting my boyfriend, everything was getting juicy ! But I texted him saying " I think our sex life is great❤️ " and he replied " I think it could be better lol" that text surprised me , I started crying after I read his text . Got so emotional that I told him I'm going to bed . He asked me if I was okay , I just told him goodnight. I feel so stupid now telling him our sex is great , I should've kept it to myself! Now I have low self esteem, what if I think it's GREAT but he think it's OKAY ?!  I'm just bummed out 😔