One that trusts her partner? What kind of question is this.

I can't imagine my long term partner, now fiancee, wouldn't trust me with something so important to us both. Why even be in a relationship at this point.

one in a stable long-term relationship where she and her partner trust each other to be responsible when it comes to risky or costly actions that impact both of them

(pregnancy is one, sure, but there's also things like blowing half your yearly salary on a sports car on a whim)

Those in a long term relationship, for example?