If it helps any, I spent virtually my whole life as you describe. Many, many failed relationships, and my first marriage failed. None lasted longer than 2 years, most never made it that long. After the last failed relationship (at that point 12 years had elapsed since my divorce), I just threw in the towel, decided to dedicate my energy toward being content with myself and my life alone. I spent a year deliberately single, working on this, and the 2nd year bought a little house in a beautiful town, and settled in with my pets to become a first class crazy cat lady.
Not quite a year later, I accidentally met a guy online (i.e. not a dating site, just a random convergence) and we fell head over heels in love. Literally each other's one true love. I was 33 at the time, and despite an ocean between us, we got together, got married, had a child, built a life, and will celebrate our 14th anniversary next May. We are still each other's one true love.
The committed, consistent love - body and soul - of another doesn't make all the things that make us INFJs (the good and the challenging) go away, though.
So much of that stuff is hardwired into our brain and spirit and other people really can't set them to rights. We live so much inside ourselves, I honestly believe it's unrealistic to believe that anyone else... even a WONDERFUL person... could set our souls and minds at ease forever, just by virtue of their love for us or our's for them.
It's a wonderful thing, but I think the most significant part of my journey was the decision to STOP looking for love, and focus on loving myself, and being a whole, complete entity unto myself, with a whole complete life that didn't have a big empty space in it, waiting for that person who would complete it. I'm not sure I would have this love if I hadn't done that part first.
So that would be my advice to anyone truly suffering from feeling unloved, empty or incomplete... love yourself. Build yourself; build your own world just as you want it. I wouldn't focus on this part but I honestly believe that those who are attracted to a whole, confident independent person are better for us than those we "end up with" because we're lonely.
Also, if possible, get a pet. Cats and especially dogs can go a long way toward filling that need to be needed.