First of all, thanks, everyone, for this thread. I read through it and there is some really great advice here!
Being in a unicorn position myself (in the positive sense, though), I can relate somewhat to tribabe's situation, so I am gonna first post some thoughts for her, and then make another post for some advice for myself.
@tribabe, that sounds like a quite toxic place to be, to me. The toxic part comes mostly from the original relationship of your partners. Have they actually, as a couple, thought through and discussed things before involving you in 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 is 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 themselves as more experienced in building relationship in general, and their own in particular. 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. It's 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 threatened 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? I'm 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 are 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. Have all three of you discussed the time, the pace, what it takes for each individual to build trust between each other?
Also, you're falling for the husband, but what about the wife? I'm 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.
Most importantly, don't let you yourself, your needs and your feelings get belittled in this 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 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 work on everyone's insecurities.
