My boyfriend fat shames me

I’ve been with my boyfriend for almost a year, and I’ve gained some weight since we first started dating. I’ve gotten a better relationship with food and gained so called “relationship weight”. When I gain weight it makes my butt, thighs and hips bigger, but this time I also gained some stomach fat. I went from 135lbs to about 155lbs, i’m also 5’6 for reference. It never bothered me because I was finally not struggling with eating disorders and felt at peace with my body. Until a couple of months ago when I was sitting on the bed getting dressed and my boyfriend gasped, then grabbed my stomach rolls and said “what’s this? when did this happen? you didn’t look like this when I first met you” and laughed. I ignored it, but since then he’s done the same thing probably 10 times. He always does the same thing. He grabs my stomach fat and says that I didn’t look this way when we first met. When we met I was 20 years old and didn’t eat enough food. He has never complained when I gain weight around my butt or thighs, but he always targets my stomach. It’s the only part that i’ve always been insecure about and now my partner is making me even more insecure. We haven’t had sex in almost 2 weeks because I don’t want him to look at me when i’m naked. I don’t want him to see me without clothes on because of what he’s been saying to me. I don’t know if he’s unhappy with the way i’ve been looking lately, and I don’t know why he would say that to me. I know that I shouldn’t let it affect me and that it’s probably “just a joke”. But I notice myself sucking in my stomach when I see that he’s looking at me, and when he tries to get intimate I always make excuses. The last time he made fun of my weight was a couple of days ago. I’m not sure what to say to him or how to make it better, but it feels like he’s trying to embarrass me and it makes me sad.