One of the biggest issues we have in finding a partner (for either of us) is that people lose interest when they find out we are already in a relationship. Even if we say we are open/poly, we are still seen as taken. What do we do?
It sounds like the issue here is with the culture, community, or scene you’re dating within. As someone who’s been practicing polyamory for over ten years, I’ve discovered that certain avenues of dating are generally closed to me. For example, when I’m at work, the fact that I have a long-term partner does come up in casual conversation. This means that coworkers who might have developed a little crush, or be interested in flirting, will file me as “unavailable.” If I wanted to pursue someone who knew me like that, I’d need to be really explicit about letting them know that I was actually interested in dating and ask if they’re interested in dating someone who is partnered.
If you’re actively seeking new partners, flings, dates, etc. my recommendation would be to focus your efforts where you’re not fighting this uphill battle of trying to convince people that you are actually available. Online dating lets you be really explicit about your polyamory and filter matches based on their relationship status or orientation. Polyamorous communities in your area are also a good place to start.