“just because it’s legal doesn’t make it okay.”

I know.

There’s a massive power imbalance in a relationship like that where the 30-something has basically total control.

I’ll not agree and say it depends on the two people. It might also not be a relationship and just a one time sex thing, or other. But I’ll agree that it doesn’t sound good in general, but it’s pretty common and doesn’t always end badly.

Half your age plus seven is the rule of thumb that I’ve heard. At 18, that means the lowest you should be dating is 16. At 32, it’s 23. Etc.

I know this rule and I find it too restrictive at specific ages, and generalizing something that can’t be only related to age. It all depends on the personality and maturity of the 2.