Spouse owns property through LLC (pre-marriage). I’m helping pay expenses but have no ownership. How can I protect myself?

My spouse co-owns a house through an LLC with their sibling. This was set up before we were married, mainly for estate planning purposes since their parents lived in the home.

The house is fully paid off, but my spouse and their sibling have recently taken on primary financial responsibility for it. The issue is that my spouse can’t afford their share of the ongoing expenses (property taxes, insurance, utilities, maintenance, etc.) without my help. To make it work, I would need to contribute a significant amount toward their half of these costs.

I’m uneasy about this because my name is not on the LLC, and I have no ownership interest in the property. Adding me to the LLC may trigger a reassessment and uncap property taxes, which could make the property much more expensive to hold.

We’ve discussed that if something were to happen (e.g., death), they would leave their share to me. But that doesn’t really protect me in other scenarios, like divorce or changes to the operating agreement. It seems possible that estate plans or LLC terms could be changed later, leaving me with no stake despite having contributed substantial funds.

Are there ways to protect my financial contributions to this property without being added to the LLC?

I want to support my spouse in keeping the property, but this would mean committing a large amount of money that I could otherwise invest elsewhere. I’m trying to find a way to do that responsibly and protect myself at the same time.

Location: Michigan