PLEASE read the whole post before replying. I promise I'll do my best to keep it brief.

Been hunting around reddit about this, and I seem to find posts/threads that seemingly have different takes on this question, depending on how it's asked or in what context.

For example, in a dating sub if someone asks if they can change what they're attracted to (usually because they find they are attracted to people "out of their league") the advice given is typically "the heart wants what the heart wants" followed by advice on how to make yourself more attractive so you can get on the same level as the people you're attracted to. There's also usually some murmuring about how it's problematic to "date down" since everyone deserves to be with someone they are genuinely attracted to, and that no one wants to be with someone that isn't really that attracted to them.

However, in other subs/threads, if a wife or husband posts something about how their SO (significant other) has gained weight/stopped trying to stay attractive, then they usually get flamed in the comments for being shallow and superficial.

These seem to be contradictory to me, since we all inevitably age. If you can't/shouldn't change what you're attracted to, and your partner's appearance changes over time (even if it's no fault of their own), are you therefore automatically shallow for no longer finding them attractive? Is the general expectation that everyone's taste should evolve to align with whatever the current state their partner is in, or is that an unfair/unrealistic expectation?

Other thoughts/tangents/critiques to how I'm framing this are of course welcome.

If you read (or at least skimmed) this far, you have my thanks. Just hoping to keep the conversation relevant.