This is not constructive advice. It is a heck of a lot more complicated than this is making it out to be. You wouldn't leave your loved one with a broken leg until the "found their own way" to the doctor.
Sure, you'd take them to the doctor for a broken leg, and help them as they get better. I'd leave someone that didn't do this.
But if the person refused to go to the doctor, what do you do then? How do you assess if they are bad enough to try to force them into hospitalisation if they aren't obviously a danger to anyone? What if the broken leg winds up causing abusive behavior (on repeated occasions) - do you stay? If their leg doesn't heal correctly and you have to care for them, can you handle the stress? What happens if you find out you aren't a good caregiver and it makes you hate your life?
I know these examples seem extreme, but it is closer to what folks sometimes deal with when their loved one has a mental illness.