Yes, that's a HUGE part of it. I've been trying to talk to them about it but I feel like I haven't been able to get a good answer.
This post was REALLY helpful. I really appreciate you taking the time to write all that out. Just a few responses to questions / some stuff I wasn't clear on:
Does he tell you inappropriate things like a "leaky hinge?" Where's the TMI wall at in this polyship? Is the problem HOW he presents the fact that he's busy already to the OSO? ... I do not know what this means. What makes this an issue? Like there's some event you really want to share with him but it is not on "your night" of the week -- he's not willing to go? Is that what that means?
I'm not sure, which is part of the problem. Maybe it would help to give an example:
I had been spending time with Hinge for the day and asked him if he wanted to spend the night. He said that he'd asked OSO to spend the night there, but that he'd drive me home. I was fine with that, I knew we had spent a lot of time together and his OSO was probably missing him. There was a potluck (a weekly thing at rotating locations) near my house, so we stopped at that on the way home. He later informed me that OSO was mad that she hadn't been invited to the potluck, because it's an event he's been bringing her to (a thing we always used to do together). She felt like it was a public event and she wasn't invited because I was there. He also told me that he would have picked her up on the way there but didn't want to ask because he thought it would upset me. I think he communicated that to her.
When he got to my house, he wasn't interested in interacting with me because his OSO was upset. He was just texting her and crying. I tried to be supportive and told him if he needed to talk or wanted a hug he could wake me up but I had to go to sleep because I was getting up early.
Now I feel guilty for having put them through that but the truth is, I don't know if I would be able to have fun at the potluck with her there. I don't know anyone else that goes to them that well, and he's sort of my safety. For example, if I start getting nervous and it's just me and him, I know I can tell him that and he'll take me home. If there's three of us, I have to wait for the OSO to be ready to leave and risk having a panic attack.
I don't want to make it sound like I'm nonfunctional, because I actually have a lot of acquaintances and friends (just nobody I'm really really close to, other than him). I go into social situations regularly. I just have to make sure that they're carefully controlled (there is someone there that I sort of know, or I can leave when I want to, etc) so I don't risk having a panic attack.
Or he's a lazy hinge not committed to continuing to court his ladies now that he's got them. Or he's a lazy hinge not doing his part keeping a healthy trio by being good about his calendar management so he spends his time well balanced across his own alone time/resting time, his time with you/his time with her. He is not creating an environment of goodwill if he's letting this "competition for my time" thing go on.
Occasionally I've brought up stuff like "I feel like you're spending more time with OSO than me, and I'm kind of bummed out because I've been going through a rough patch and your support really helps me" and he says stuff like "Well, she always asks me to do things first." I get the sense in general that he doesn't really do time management/courting and just does whatever people ask him to. Which doesn't make me feel especially wanted. He talks a lot about being afraid of losing one or both of us, and that makes me feel like he's motivated more by fear than by actually enjoying our company.
You seem to worry a lot about her feelings. Why? Can't she be allowed to own her own feelings? [...] loved ones and that's a line with him. Isn't it a line with him? Why not?
I care about her, and I think she's a good person and that she tries to be supportive/respectful, even though she's not somebody I would hang out with. I just want things she doesn't want -- like the event example. I don't want to ask for things that depress her or cause problems with her and Hinge (both for her and the fact that it will make my relationship with Hinge worse)...
I don't think he knows what his lines are because he's never been in a poly relationship before (he doesn't even identify as poly, which is a reason I always classified our relationship as a friendship).
Is he doing his hinge job well or not?
I'm not sure. I'm trying to be objective, but I am aware that I've had a tough few months with my friends leaving town and all, so I'm probably more sensitive than usual. I've also only been the hinge or in a secondary relationship to someone's primary, never in such an undefined situation (he says he thinks of us as equal, that's actually a lot more stressful to me than being secondary because it complicates decision making.)