Here’s the thing, reader. You’re not “new to polyamory”; you’re polyamorous under duress. Which, in essence, means you’re monogamous but are being subjected to an ultimatum by a person who is taking advantage of your obvious devotion to them. That ultimatum is “polyamory or bust”. This is a manipulation, not a relationship, and it’s definitely not the kind of behavior that you want to continue greenlighting.
Let’s break the situation down by red flags:
“I was with D for two years, and it was bumpy.” First red flag. Couples who decide to open up their relationship during a period of turmoil as a means of “fixing” the relationship rarely - if ever - last. It’s not that dissimilar from the practice of couples deciding to have a baby to mend the relationship or bring them “closer together”. In stark contrast, couples with a history of happiness, stability and compatible communication strategy who decide to open up their relationship have a much higher success rate because they’re already starting from a place of high satisfaction. Also, the fact that you describe your prior two year attachment to D as “bumpy” doesn’t bode well for any long term commitment, monogamous or otherwise.
“We love each other dearly, but he ended things with me because he was too focused on making me happy and not himself.” Second red flag. My own reservations around the authenticity of D’s reasoning aside [insert infinite sideye here], he ended the relationship with you in lieu of initiating a dialogue about his issues with the relationship and offering to put in work in order to save it. In doing so, he also took away any opportunity for YOU to put work into addressing the issues at hand - should you have desired to, of course. In short, he chose the easy way out. Do you really want to be in a relationship where the other party isn’t willing to fight for it?
“So in the time we were broken up - two weeks - D went on a date with a woman, she got kicked out of her house, and he took her in.” Third red flag. To say nothing about the character of the woman he’s cohabitating with, offering his home up to her after a single date is at best a terrible judgment call and at worst an abusive tactic. My hunch is the latter; that he’s looking for someone - or someone(s) - to control, and a partner is much easier to manipulate when you’re sharing the same living space. But regardless of his motivation, again, he’s failing to execute good judgment, and that alone means he’s not dating material.
“So we got back together, but only under the condition that he could date us both. I love him so much and want to spend my life with him, but I don’t know his other partner and I feel super uncomfortable.” Fourth and final red flag. No sustainable relationship with healthy power dynamics kicks off with an ultimatum. By reluctantly agreeing to D’s terms - a relationship structure that’s completely foreign to all involved, no less - you’ve now set the tone of your relationship with him to be one of submission and dependency. Trust me!
Lastly, even IF you and D never broke up and he had met this other woman with the interest of pursuing her, there are a number of steps he should have taken prior to initiating non-monogamy in order to maximize the potential for success. He should have been transparent with you about his desires while still prioritizing your comfort and feeling of security in the relationship. If you expressed interest in learning more, you two should have set off on a journey of exploration TOGETHER. Reading about non-monogamy, listening to podcasts about non-monogamy, going to non-monogamous social gatherings and cultivating friendships with other non-monogamous folks, etc.
Then, after you both negotiated a list of boundaries - and ONLY IF you were truly ready for D to begin seeing this woman - you should not only be privy to information about her, but also provided with opportunities to meet her and get to know her better. D would have a certain amount of responsibility to cultivate a familiarity between the two of you, because again, he should be organically invested in the healthiness and happiness of his partners.
Reader, you deserve SO much better, and I PROMISE that you’ll find it. If I were you, I’d GTFO of that toxic cesspool and take D’s other partner with you! #GirlPower