If you were to ask me for my advice, which you won't, I'm not sure I would give it to you. I mean, I could, but since you probably aren't in a place where you can accept what I'm saying, it would probably not be helpful. Instead I'm here having this conversation in my head with a hypothetical version of you. Maybe I'm just having it with a hypothetical younger version of myself.
I remember being where you are. Many times. In it neck deep with a person who either wasn't as committed to me as I was to him or who loved me but whose modus operandi was to seek distraction from life's pressures by seeking the attention of other women. (No, I'm not speaking of any one person in particular and even if you think I am, remember this is a hypothetical conversation, so those were just hypothetical men. Or women. Or cats. Or whatever. I could never trust my cats to be faithful. They'll let anybody pet them.)
In those relationships my younger self tried to fix the problem by controlling the other person. My younger self didn't understand yet that she was substituting the love and adoration of another person for true self-validation. You see, I didn't believe I was worthy of love. I didn't accept myself and my flaws. Somewhere inside my brain I thought that if someone else just loved me enough that meant I was good enough to be loved, and problem solved! Except that the problem was even farther away from being solved than ever because I was approaching it backwards. I was making my own crazy and even worse, I was telling other people it was their fault I was unhappy because they didn't love me enough or they couldn't stay faithful to me. If what I did to myself was wrong, what I did to other people in my life was downright cruel and heartless.
Eventually I had to learn to let go of the need for an illusion. I had to learn real acceptance of myself, of my circumstances. I had to take an inventory of myself and discover not only things that are awesome, but to take stock of the flaws in my personality that aren't so pretty.
What I would tell my younger self now? This: That guy you can't trust? Maybe he can change. Maybe he can't. But as long as you twist yourself into a pretzel trying to keep him in the emotional handcuffs you are creating I can guarantee that the only thing you will accomplish is to make both of you miserable. I know that riding herd on someone to make sure they're not doing something you don't want them to do will make you both insane. Don't you respect them enough to let them manage their own lives? If you assume they're incompetent and can't be trusted to do things right without you checking to make sure they are, what does that say about YOU? Why would you even want to be in a relationship with someone you can't respect and trust?
Loving and caring about someone isn't enough to guarantee that a relationship will work or that it will last. You can love someone with all your heart and soul and that relationship can end for many reasons. Maybe its a bad fit. Maybe the other person is struggling with their own problems or addictions or weaknesses that make it hard for them to be a good partner right now. Maybe they will never get any better than they are right at this moment. Maybe you will never get any better than you are right at this moment (you probably will).
We all want the happy ending. We love the fairy tale. We want with all our hearts to believe that love really does conquer all. And I believe that it does, but not in the way that most people think. Being alone, being lonely, can really suck sometimes. I've had times I was so lonely I felt I would die from it. But I didn't die. All that time I wasted thinking other people were the solution to my problems, and I had to relearn the truth that the only solution to my problems was ME. I could run away from them, I could try to solve them, I could try to drown them in alcohol or pills, but ultimately the only person who belonged in the cage match wrestling with my demons was myself.
There is nothing in this world that will protect us from being hurt. We'll make bad choices and have to live with the consequences. Other people will do things that we don't like or that are painful for us. Things completely outside of our control will have an impact on us that hurts like hell. I tell you this now, hypothetically, that the sooner you are at peace with these facts, the greater capability you will have within you for true happiness.
Once your ability to be happy doesn't depend on other people, you are free to live your life.
Your problems will still be there, of course. This person who is still hurting you might still be part of your life. But you can let go of him. Who knows? Maybe he'll keep walking right along beside you. Maybe he'll grow into a really great partner, maybe he'll have some success wrestling with his own demons. Maybe he'll walk away. Maybe you'll walk away because you find its the best way to help yourself. I don't have those answers. Not even hypothetically.