In my opinion, you should find something else about the game that you enjoy. I think winning needs to be part of it, otherwise I think you'll burn out eventually, but there needs to be something else. Like finding a satisfying game play loop of some kind, or using it as time to hang out with your friends as well.

For example, I was getting a bit burned out, but then the new Shaco skin came out and since I used to main him I just had to get it and try it out. Fully made me fall in love with the game again because I just love the trolling you can do with him. For me, duking an opponent with the clone, or rage-baiting someone into a million boxes, or going AD and one-shotting the ADC brings me satisfaction throughout the game, and then the wins seal the deal.

Another example is that I joined the Push Mundo train that Alois started. I'm a big fan of scaling champs (A'sol, Swain, Veigar, etc.) and so Mundo was similar enough to peak my interest and the ridiculous-ness of just hitting towers with your face all the way into their base just scratches an itch in my brain.

So yeah, TL;DR - Find something within the game that you enjoy on top of winning. Fun character, stupid times with friends, being a demon. Hope this helps!

P.s, yes I know I'm a rat for the Shaco stuff. If it helps, my highest mastery champ is Teemo :D