in The Beginning, we are born. we are a blank slate with no sense of "Identity" -- this doesn't form until we are 2 years old.
then we learn the word "Me" and it's all downhill from there -- our entire vocabulary revolves around the words "I, Me, Mine" -- this is called the "terrible two's".
(note: some people NEVER progress beyond this point).
eventually (ideally) we would outgrow our "terrible two's" and learn to extend this same sense of "Identity" to include other people -- this is called "empathy" -- we learn to care about other people, besides just ourselves.
(it often starts with tribalism/race/gender/religion/
those-who-"look-like-us"/etc, but that's another thread -- let's face it -- it HAS to start somewhere -- these are the "baby steps")
at some point the scale tips in the other direction, and we realize, we are actually NOT the most important person on earth anymore.
--> NOW you are ready for a successful "relationship"
(google: "Han Solo's Character Arc" -- from selfish to selfless -- he learns to care about OTHER people, MORE than his own damned self -- only then, can he "get the girl")
I met my wife when I was 13. I've been married (to the same girl) for over 30 years. (we've been together as a "couple" for over 35 years).
people ask me "what's the secret" to a happy relationship..? my answer...? (in 3 words or less)...?
"Get Over Yourself"

LOL
I think a lot of you guys are approaching this from the wrong angle. I'm seeing a lot of the words "I, Me, Mine".
think instead about what you bring to the relationship -- not what you can get out of it.
just a general observation (not directed at anyone in particular). cheers.