First of all thanks everyone for this thread - read through it and there are some really great advices here!
Being in a unicorn position myself (unicorn here in the positive sense though), I can relate somehow to tribabe's situation, so gonna first post some thoughts for her and then make another post for some advice for myself.
@tribabe, for me that sounds like a quite toxic place to be, and the toxic part comes mostly from the original relationship of your partners. Have they actually as a couple thought and discussed things through before involving you into the scene? Their behavior doesn't sounds very empathetic towards you here, whether they actually mean it or not.
I believe starting a new relationship with only one person requires a lot of maturity and understanding of thyself, and in situations when there are more than one person involved it can be even more demanding from the personal development and understanding point of view.
It sounds that you are still quite young (23yo) so I assume that they as a married couple are (1) been together for some years already and (2) perceive as more experienced in building relationship in general & their own particularly. Thus it may be easy to fall for "their way to do things" in building your three-way relationship together, but it doesn't necessarily have to be that way. And good that you have expressed your needs clearly.
Hopefully I'm not jumping into assumptions, but from your last post seems that it is the wife who feels insecure and threaten by you?
He also mentioned that she said that if he ever found himself to be in love with me, our relationship would have to end.
This sounds like a very big red flag - if not love, then what's the whole point of having all three-way triad relationship? (assuming that's what you really want)
Is this married couple also new to polyamory and just opening up? It may be scary for them as well, and bringing to the surface a lot of inner insecurities - as they also try to defend their old dynamics.
If you really want the relationship to work, there's a lot of open discussions to go through. You said it's a new triad, but haven't quite indicated how long you've been in it together, so have you (all three of you) discussed abut time pace what it takes to each individual to build trust between each other? Also you're falling for the guy, but what about the wife? Not trying to point out that it must happen that you'll fall for her too, but whether or not you become romantically or sexually attracted, there's a lot you can both do to build a bond based on mutual respect, trust and compassion - and as a result it will be easier to further develop a bond with the husband.
Quite a long post already... but most importantly don't let yourself, your needs and your feelings get belittled in that situation (at the moment with all the rules and couple privilege it sounds like the couple is doing so). Be brave and discuss with them whether they actually want to be with you authentically in a supportive and flourishing way - or just keep you as an entertaining addition to facilitate threesomes. If it's the latter one, they're not worth of your time and effort. But if they want to get to know the real you and how to be with you, then you can try to help each other to work on everyone's insecurities.
