zachtos,
Please take to heart the well meant intentions of everyone here. No man will truly understand a woman, they are mentally unstable from the get go. This "woman" is either manipulating you through guilt and fear on purpose or just by sheer use of woman logic.
She realizes that you feel obligation towards her and uses that to make you feel guilty.
You are playing into her hands every time. I have been married for 21.5 years. I understand these qualities in a woman (mind you I am happy and 95% of the time I do not have any regrets). It is tough living with the same woman for many years even when you are happy and still love said woman. From your comments, there is NO LOVE in this relationship, there is only selfishness (obviously I am assuming you have been 100% honest with all of this). You cannot build a successful relationship out of the train wreck that you are in. It is damaged now and will only get worse. You have no real obligations toward this woman, you are not married, hopefully she is not pregnant, and you are not living together. You are free to do as you wish. Just remember to treat her as a human being in breaking up with her. Do it tactifully and respect her feelings, even if she doesn't respect yours. If she does something drastic, that is her choice, not yours. You need to take the responsibility to truly end a relationship that has already died. Take heart, you will feel loneliness for a short time, that is natural. You will find other fish in the ocean,
but for now just fish, get a bite, throw it back into the ocean. You will find the prize catch for yourself when you least expect it. But above all, be a man and treat women like you are in charge of yourself and you will have no trouble meeting other women.