Privacy

You can:

1. Use an email alias to sign up so that information isn't connected to you personally.
2. Install it in a work profile for additional sandboxing
3. Use something like MockMyGPS to fake your location at any given moment
4. Request to use a different app that accomplishes the same thing but with a reasonable privacy policy and E2EE like Paralino.
5. Reconsider your relationship with this person.

How is this person forcing you? Are you an adult? So they provide the material benefits for your life, like good and shelter?

If "yes" to being an adult, and then "no" to being a dependent or an employee, then this requires a lot more conversation.

If you have an android phone, you can make use of FDroid and Islands/'Insular' (without root access) to have a separately secure side of your phone for apps and system settings.

For example, I loaded all of my work apps in there and then set a VPN so that ALL OFF THEM were unable to connect to the Internet when the VPN was offline, so that the ip-location and the DNS didn't tattle on my travels. My regular phone use was secured away to the point I couldn't accidentally send photos from my regular photos app through my work email app, only the second copy that lived within that 'secure folder' style partition.

Obviously your situation is harsher but at least you can mitigate a bit by being able to offline the app for considerable intervals, this way.

Good luck. I hope that you share more of this story.

Edit: I see you are stuck on iOS. I have zero suggestions for your specific situation besides "work on the relationship, and your always have the right to walk away from the business or the adult relationship if it's untenable."

I was in a situation where I saw tv commercials for the first time in years. And I saw one for life360, and it was so unhinged. Something about a mother going on and on about how her child would die, and the solution was this app.

Who forces you? Employer: they buy you a new phone. Otherwise: ignore, call the cops, or dont use a smartphone

Is carrying a second phone logged into a junk account an option for you?

Your explanation lacks enough detail to give a proper answer. Seems like there are some petty important details being left out of this story.

That said, I'd just use an old phone and turn it off/stick it in a blackout bag when not required.

Look, I get I'm being a bit of an asshole with this answer, but given what little you've provided it's the only one I can think of: get a phone (a google pixel) that can install an operating system that actually cares about your privacy (grapheneos). Then use its sandboxing to protect you from privacy invasion generally, and Life360 specifically.