My boyfriend (M29) is obsessed with fitness and me (f27) loosing weight

I (f27) have been dating my boyfriend (m29) for about 9 months and it’s been amazing except for one issue that has become increasingly difficult for me to ignore: he’s fixated on the idea of me losing weight.

For context, I’m 5’8” and 148 lbs. I’m not the skinniest or the most athletic person, but I’m not overweight either. I’ve struggled with my weight and body image since I was a kid, so it’s always been a sensitive topic for me.

I’ve told him multiple times that his comments about my weight or suggestions about how I should eat or work out make me feel bad. Every time, he apologizes and says he’ll stop, but before long he starts making comments again. It almost feels like he can’t help himself.

What makes it more confusing is that he genuinely seems turned on by the idea of me getting fitter or skinnier. Talking about fitness, dieting, or me losing weight is something he gets excited about. For more context, he’s extremely athletic. He played a Division I sport on a full scholarship, and fitness has been a huge part of his life. He’s also a very analytical person who tends to see things as objective facts rather than emotional issues.

From his perspective, he thinks he’s helping me improve. He doesn’t understand why I don’t want him acting like my coach or nutritionist. But to me, it doesn’t feel supportive—it makes me feel like I’m not enough as I am.

He’s even said that fit people are generally “more elite” and more attractive. Hearing that has really affected how I see myself in the relationship. I’ve been going to the gym with him for the past few months, partly because I genuinely want to be healthier, but also because I want him to desire me. When we’re there, I notice him looking at the very fit women, and it makes me wonder if I’ll ever measure up. His ex girlfriend is also very short and very thin. He told me this morning he would be me jeans when I got to 135 lbs and a necklace at 125 lbs.

What I can’t understand is this: if physical fitness is such a major priority for him, why did he choose to date me instead of someone who already fit that lifestyle? His constant focus on “bettering” me has started to make me feel unwanted and undesirable.
Am I being too sensitive because of my own history with body image, or are my boundaries being crossed? Is this his way of showing love and encouragement, or is it reasonable for me to feel hurt by the fact that he can’t seem to let this go?