AITAH: Did I cross a line by commenting on my boyfriend’s body and that he should work on himself physically?

Hello, can someone please tell me if I am wrong in this situation? I’m open to honest feedback.

Me (M23) and my boyfriend (M25) are long-distance, and been dating for 3 months now. A few days ago, I asked him to send me pictures of his biceps and abs, and I jokingly added a comment like “I’m thirsty for it.” I’ve always been very attracted to traditionally masculine features, such as strong hands, arms, and an overall manly appearance. He is athletic and plays sports, so I expected him to look healthy and fit.

When he sent the pictures, he looked much smaller and skinnier than I expected, I was a bit shocked, and it honestly gave me a bit of an ick, but I didn’t say much at the time. I know he trusted me by sending those photos, and I believe he felt safe and unjudged when it came to his body.

A few days later, I brought up the topic and told him that he should eat well and look after himself. but I never told him to go to the gym or build muscle. I thought he would understand what I meant, but instead it completely ruined his mood and his day since I said he didn't look manly. I clearly hurt his feelings, and he didn’t text me for about an hour afterwards.

When he confronted me, he told me that those kinds of comments aren’t something you say to someone you love, and that hearing it from me was especially painful and rude, especially when it came from me. Which is true!

I took accountability, apologized, and we moved on. We been now dating for 6 months and I still wish he would do better. I don’t feel like I’m asking for too much and I believe a man should look after himself and make an effort to work on himself, just like how many men expect their partners to look good for them, something I consistently do for his attention.

How can I communicate about this with him in a way that isn’t hurtful or damaging to our relationship and his feelings? Or should I just let it slide?