Acceptance is Key
Can I turn cat into a dog? No, I cannot! My point is again, we cannot change anyone but ourselves. Also, if you do love someone learn to accept their flaws; if they are not hurting you or anyone else then my advice is always acceptance is key. Especially if this is someone who you love and want to want to have a lifelong partnership with.
This is not time to play the “Poor Me” card. Self-pity is unattractive and quite frankly prevents you from ever evolving and learning your life lessons. You can absolutely stay in the toxic relationship however it’s an exercise in futility if you truly believe you have the power to change your partner. You are not Harry Potter or Glenda the Good Witch with a magic wand you can use to cast a spell! We have free will and if your partner chooses to change, then he or she will do that when they want to (if ever.)
You are the Only One in Charge of Your Life
One book I can recommend is called "Codependent No More: How to Stop Controlling Others and Start Caring for Yourself" by Melody Beattie. I leave you with one of my favorite quotes from her brilliant book to inspire:
"I used to spend so much time reacting and responding to everyone else that my life had no direction. Other people's lives, problems, and wants to set the course for my life. Once I realized it was okay for me to think about and identify what I wanted, remarkable things began to take place in my life" - Melody Beattie