No. It is supportive. You are normalizing removing a gender stereotype. I.e. instead of saying my wife/husband which inherently brings a gender, and then also stated sexuality, you say partner, removing the gender statement. In so doing, you both help defend others to also be able to say it without forcing them to share their sexuality while also normalizing the removal of an over emphasis on gender with something that doesn't fucking matter.

Not at all appropriation, if you feel it's a better descriptor then go for it!

On top of that, it's really good cover to have more straight people do that so it's not as big of a tell when people in queer relationships say it out of necessity. Similar to how having more cis people display pronouns makes it less likely for trans people to get singled out due to it being more common. - Finn (fae/she)