Even if you meet someone to whom you think you have no previous connection, a 10-minute conversation almost always reveals that she went to high school with your college roommate, used to be on a volleyball team with that girl from your book club, and had a six-month stand with your favorite barista.
Queers don't tend to expect our dates to come into our lives completely free of prior complication.
In general, allow your friend and your sweetheart to decide how much contact they want with each other, and don't push them to associate if they're not into it.
Queer communities are often small and insular, and once you've found one, you tend to hold on to it for dear life.
It's difficult to meet people you're romantically interested in beyond an already-defined circle, and outside of your city's queer scene, most people you run into are likely to be straight.
Whether you're gay, straight, bi, or not into labels, dating a friend's ex can absolutely be done without sacrificing your friendship — you just have to follow a few simple guidelines.1. It's common to assume that anything shared with you is by default shared with your partner as well; however, your friend might be much less comfortable speaking to you in confidence if she thought the details of her personal life were going to be relayed to someone who used to share her toothbrush.
(I'm going to use female pronouns for your friend, and male pronouns for your sweetie, for the sake of simplicity; however, every rule here applies no matter the genders of the participants.) Keep your friend's secrets.