Partner (40m) Has a crush on someone in a different continent.

TLDR: Partner says that he wants to see where his crush goes.. so he won't keep wondering.
R (40m) and I(35f)have been friends for 10 years and been partners (for lack of a better word) for 3-4 years.
He is my rock and understands me more than anyone else.
Yesterday, he told me that he met his girl online and has a crush on her and wants to see where it goes. I feel betrayed cos I finally realized that he's leading me on and prob keeping me as his back up plan. I deserve better.
He doesn't have a job, smokes weed and drinks everyday, plays video games and talks to his friends over zoom all day (that's where they met).
Oh and I paid his rent for last month and send him money for food etc.
He said he wants to find himself and not live his life wondering if he made the right choice being with me.
I'm just numb and feel useless.
What can or should I do? Why do I feel so ****ty ? Am I not good enough? Am I not pretty enough?


Source.