Look up username "Maca" and read his posts. He's my husband. He definitely felt similar to you.
He doesn't post anymore, because he's living his life happily and hates to type.
We struggled for a long time and there are still moments that crop up.
I imagine, one is on its way actually, because the 9th is our anniversary, but becuase it falls on a Monday, we can't go do something special that day (he'll be working) AND my boyfriend has Mondays off work, so will be home with the kids and me.
BUT-all in all, great things have happened in the last 6 months and it seems to just keep improving.
So, yes, there are people who it just doesn't work for. But, there are also people who feel the same you feel now, but find with time, love and lots of talking (sometimes to other people) along with plenty of "fuck the talking lets just be together for now" moments-find their way to a happy, successful, very worthwhile place in poly.
(you can also feel free to read through my previous posts, but I gave you his username because he was the one in your shoes).