I'm not going to judge the people considering AI lovers. They're trying to fulfil a basic human need in an increasingly disconnected and uncertain world. We can't stop it, eventually it will become normalised and I'm concerned for everybody's safety.
Most people who do this aren't going to host their own models, they're going to use commercially available apps.
Aside from the vast amount of money that'll be made by the company that gains a monopoly in this space, because that's generally what happens in tech these days, the data they gather WILL be used to improve the systems that already try to manipulate you regardless of whether you use an AI companion or not. It'll make targeted advertising seem as innocuous as billboards by comparison.