Get over the 4-5 year hump in a relationship then you can claim it's stable, imo
psychology even has studies showing that it's the "worst" at the 4-5 year mark and then climbs up iirc. Been awhile since I studied such things. I also would say it's best to officially move in and live together for awhile before getting engaged. But, that's me.
Anyways, super nice to see more of this. Love this and the prior in the series.