Please let me first say I feel for you, and I appreciate it is a difficult situation to find yourself in. I am not taking anybody's side or approve of her behaviour, not because I disapprove of it but because she's not mine to approve or disapprove of. As much as I sympathise with you and your not willing to accept what others her have to say to you, let me lay it out straight to you.
She is not on the wrong path; you perceive her path as incorrect. She is not "not herself"; you have a different idea of her, which you want her to conform to. She had not strayed; you want to keep her on a tight leash. It is not "reason and goodness" you want her to listen to; it's your ideas of them. Her heart is not for you to judge "cruel" or her exterior "cold and twisted". She doesn't need your help with her healing or to make her "susceptible" to her love for you - there no need for euphemisms - if the love's gone, it's gone, if it's there then it doesn't need your help or a spell to make her susceptible to it. This woman and you were not "literally made for each other"; she doesn't belong to you (or anyone else for that matter) while you want to control her. (It's more likely she was made to teach you some lessons, such as not relying on others for your happiness.) She didn't succumb to demons or temptation; she just chose a different path from what you had in mind for her and your unacceptance of it doesn't make it incorrect. She doesn't need clarity, you do, because you don't accept it's not up to you to decide what she needs. The only person who you can train to make you happy and control is yourself, and until you know that, it's you who needs clarity. You became dependent on her for your happiness and life satisfaction and here's your lesson; it's not her demons you need to worry about, it's yours.
Take a long hard look at yourself because that's the only person you can change and influence without meddling. She has free will and she makes her choices, and you must let her, but you are seeking help with manipulating her free will and taking control of her.
"Go home and cry" is not "the only thing" you can do; it's the only thing you choose to do. This forum's not the only place you have to turn to, and it is really worrying that people turn to magick so they can influence others or their paths.
I don't know you and I'm not here to judge you buy I can tell you that if it was my husband putting this or similar on such forums, I'd run as far from him as I could, and with protection spells for myself too. It's the most manipulative thing imaginable your trying to achieve here and I pity you and the person who helps you to do it if you ever find such a one.
Love and healing to you.
I'm sorry that you feel this way.