Is it me being sensitive or his shallowness

Me and my partner have both put on weight (as you do in a relationship at one point or another) he remains negatives and makes comments all the time about himself like he’s fat etc. I suggested we hit the gym for the month and tone up before it gets out of hand. He hasn’t joined, his excuses are there’s no swimming pool, it’s expensive, I’ve joined and gone without him. I’ve now noticed he hates me in my dresses, says I definitely shouldn’t be showing my legs etc and need to start wearing tights… he now says everything is tight on me even though it doesn’t feel like it..he’s making me feel insecure and I just don’t know why… like he even said why am I wearing shorts to the gym. All this and then has the audacity to ask for sex constantly…I’m questioning if its me