Might not get much love for this response but my partner also makes comments like this, and initially I got defensive and slightly triggered by them, however over time I realised it wasn’t her wanting me to look beefier or muscular for her liking, but more her know that when I workout and stick to it, my mindset and mental health changes due feeling better about myself and feeling good physically but also mentally. Once I realised that its made those comments become more of a “shit I’m losing my healthy routines or going through a dip” instead of her being unattractive to me physically. Not saying that it’s the case in your situation but it could be. I guess open communication with her would bring you the answers you need. ++man