No bad impression at all. I hear your pain. I'm sorry its been hard. Whining usually is about pain.
Just in grown ups it changes into grown up pain... if that makes sense.
I'm whiny today because I feel yucky. We all do it sometimes when things aren't easy.. I get it.
I am not sure what this decision is that you think you have to make. Is it anxiety that SOMETHING is happening and SOMETHING could happen? I am wondering why there is a need to rush... which I mentioned previously in my last post. What decision do you have to make? Did I miss something. Sorry if I did.
This guy needs time I think. She isn't going anywhere, you aren't going anywhere, the love you feel (and she feels) isn't going anywhere. Take a breath, get some sleep, let them figure out some stuff and leave them to it for a bit. If I were in your situation I would do this last bit for sure as there is nothing more distracting to a persons process than someone that is coming on strong with their need to know RIGHT NOW what will happen next.
This might not work out for many reasons, but at least its a start into poly. If she decides that she can't be with you because of him then you will survive and will have learned something. Who knows, it might come around again. I am 42, I have partners that have come around over and over again who are lifers now with me. I love that sometimes I don't see them for years and then, they are their again. Still themselves, but having grown and matured and become more lovely than ever. When I was your age I thought that was it forever.... nope, things change with time and people change. I wish I had trusted that back then and relaxed, rather than allowing myself to disintegrate in pain and anguish over situations I was in.
Give yourself a break, you are doing fine in this. Take some time away from this and do some self care. The most important person in this is you and your relationship with yourself. Take care of yourself first.