Afraid my SO isnt attracted to me anymore because of how small i am

Brittney
I've always been a small girl.. Min 125lbs Max 140lbs(during period time).. Never liked It. I just never felt healthy being skin and bones... Until I started working out and taking mass gainers. I finally went up to 155lbs... After another ectopic pregnancy I went back down to 140lbs.. I've been wanting to discuss trying for another baby next month but I got some sad ass excuse about how he thinks I should put my weight back on before we start trying. Later on I asked if there was anything about my appearance he would change... Quick as shit, "I wish you would get back thicker again".... I've been trying to put weight back on but its like my body is meant to be small. I already feel as if this world is becoming a constant competition between "thick" & "skinny" but now im feeling like Im not good enough for him and I have to do all in my power to keep his attention. This is another reason I HATE being so small.. Majority of guys like thick or big girls, can't blame them I think their the most beautiful people inside and out but it sucks for me when it comes to keeping a relationship.