I'm trying to think a bit wider and challenge myself on how I'd feel if my DH lost loads of weight, and started getting into ballet. To the point where he wanted to do a ballet competition and have lots of pictures taken of him jumping in the air in a leotard to put on social media.
Being completely honest, I'd struggle with it.
DH and I are both pretty lazy and overweight, I could imagine that if DH started to get into the gym heavily it might put a bit of a strain on our marriage. Just because it would change alot of aspects - e.g if he became health obsessed well there goes our cosy'ing up on the sofa with a Chinese on a Friday night. I do see how one person in a relationship making a huge lifestyle change can threaten a relationship.
I love my DH so I'm sure my marriage would survive but I guess I would go through a period of confusion, rejection, hurt, fear, and doubt and I'm sure we'd grapple with how to find a balance.
But also if my DH went from being one sort of a person to an entirely different sort of person - I would have to question whether we'd simply grown apart. Because I know I wouldn't have married a body builder. It's just not my thing.
So while I don't think you're wrong to pursue your interests, and I don't agree with how he's spoken to you about it - I can see that it does or can bring up real make or break conversations where it doesn't simply boil down to 'my DH doesn't support me and won't work out with me therefore he's a selfish prick, isn't he?' type of straightforward response. It's more nuanced than that.