I will be brutally honest here. Unfortunately I can't think of any other way to say this. She is purely a manipulative person and nothing in what you've said garners any kind of sensitivity from me for this so-called friend.

She is in no way your friend IMO. Look at your experience with her from the start. She was upset at the very start that she had been "sectioned" First warning sign. Why is that? They noticed in her that she was someone that needed to have special handling. This was before you knew anything else of her and unfortunately because you are a sensitive and grace filled person, you let her in.

The problem I see here, to be completely honest is that you got trapped in a situation with someone that does exactly what she's doing to you. She says she has no friends. This should make you question why. IF it's true, that people in her family and friends have cut her off, considering likely they all have known her much longer than you, there must be a reason. Likely tied to the behaviors she is exhibiting to you.

I speak from my own experience in that I tend to be the type that does much of what you are doing but have many times, been taken advantage of emotionally. I have time and again found myself supporting someone that only takes, only leans on me and never gives anything back.

There are a lot of people that are this way. They know only how to manipulate and make people feel sorry for them and offer a shoulder to lean on or cry on. Some go as far as making up stories but most times at the very least their stories and their life situations are grossly exaggerated in order to garner support from others. No, I cannot say 100% with certainty that she is doing those things but I can say from an experienced viewpoint based on your description that she very likely is this type of person.

you have your own issues, you have your own life, family even if only a wife to take care of first aside from being able to care for yourself first this is the last thing you need right now if ever. If someone continues to leech off of you emotionally it can only do you harm, your family and everyone around you after awhile. Your wife's concerns are very valid and you should heed them and not only take a break but break it off completely from her. I know that sounds uncaring but if she sucks everything out of you leaning on you without ever being truly a friend, where will you be? you won't be able to support her anyway and God knows that you won't be able to be there for those that truly need you to be there for you.

If my analysis is correct, she will find another to manipulate and take from. You're not important enough to her to give to you what friends give, move on, please.