If you were to judge monogamy by the shit that pops up in relationship advice threads, people would have a bad impression of it as well!
That’s the truth.
My day job is FinTech/tax adjacent, so I have to give you collectively (and your collective web of relationships) credit for making the home ownership work. The overwhelming majority of humans can’t make tenants in common between two people work.
Personally, I’'m not particularly close with my family for other reasons, so being ‘out’ isn’t a real concern - given a wife and girlfriend in that long-term context, I’d write the requisite will / medical POA to be fair, and to ensure that blood relatives aren’t executing either.
I’m somewhat close with folks at work, but I WFH for a company that’s fairly progressive. One of the people I started with recently asked us to address them in a specific way, and I couldn’t be happier for them. If I called my boss “Joe,” and they asked me to call them “Mr. Smith”, that’s no different.
I very much like your strategy of “truthful but no obvious” There isn’t a need at work for a full-fledged explanation of my home life, but I also work with good people who don’t blink at the miscellaneous terms I (or they) use to describe the people who are important to us. That’s how it’s supposed to work - we all share what we feel comfortable with, and other people share in our joys/sorrows regarding the same. Only the level of detail changes, really.