A Lie of Omission

I've been in this open relationship for over a year now. My partner, Sam, is understanding and we communicate openly about everything except one thing, me. I'm transgender and have been on hormones for three years, but recently, I started taking them inconsistently due to some personal financial struggles. When I had the chance to go to an event this weekend with my girlfriend, Mia, who doesn't know about my hormone use, I skipped mentioning it to her. It's not a lie, exactly, just an omission, but lying by omission feels like betrayal. The guilt is overwhelming because I'm letting someone into my life and withholding such a fundamental part of myself. This isn’t about sex or kink, just honesty with those closest to me, something I've struggled with ever since coming out.