I know...

...I will always be second best to you. Second option. Second, or maybe even third or fourth or last.
...there's nothing I can do about it. This line from a song, "I did my best but I guess my best wasn't good enough," has never been truer to me.
...only time can tell if I'll ever be worthy for your time and attention.

And, most of all,
...that I am already so tired of proving myself worthy. It's time to stop. Time to let go. Time to do things only because I want to. Time to give importance to those who gives me importance. Time to choose happiness. Time to live for myself and for those who matter. It's time.