Bottom line is that you wanted to continue this "relationship" at any cost, but you are beginning to realize that it keeps deteriorating at an alarming rate and is about to spiral into a maddening new direction and just maybe, this might be the end of the line for you.
You have no control over the decisions and actions of your "girlfriend". You can only control your own actions with the caveat that you do not want to be stuck in reactive mode, but rather remain steadfast in standing your ground on actions and decisions that are vitally important to you, your life and your future happiness.
It is as if you were transfixed by an oncoming train barreling in your direction and you are so frozen in fear you cannot move to step aside and avoid a collision.
By supporting her in whatever she wants to do like a good friend would, you are opening yourself up to a world of heartache because you are still fully invested in a "relationship" that only exists in your head.
She has made her decision, despite your wish to the contrary and is merrily moving forward with her plans. That is her right and I can understand a woman determined to have a child above all else. Even you. I cannot say whether I agree with her decision or not, it is a desperate move.
The fact that she has mental issues is not to be taken lightly. None of the fear scenarios you have presented can be dismissed. Yes, you may become attached to the child - have you considered how much worse it will be to know that here is a child that may need your help, but an emotionally distraught mother will not let you near? much less help?
You will have no control and no say so and there are her family to consider - all of whom have mental issues.
This is truly a train wreck waiting to happen.
Forgive me for saying this, but generally speaking, a forty-year-old man, with a good income and stable finances, who is caring and kind, introvert or not, is a good catch. Yes, I know, you would prefer to make this relationship work, but the truth is, there is no relationship to salvage.
At most, you can entertain friendship, but in your case, that is fraught with even more landmines.
Do the smart thing and do not go there.
Sure you cried when you broke up - why not, any man worth his salt will shed a tear and feel depressed after a break-up with someone he cared deeply about. It makes you a more loving, desirable human being.
The only mistake you made is that you gave in to your fear of loneliness and you remembered only the good times and saw only what "could be".
That is just human and normal.
We all want companionship and love in our lives. It is OK to want that, but you also have a duty to yourself to protect yourself from a situation that you already know will be potentially disastrous for you and truly impact your life in a mega negative way for years to come.
Do not do this to yourself. You deserve a great relationship with a fine woman and there is no reason you can't still find that - none.
There may be the right woman waiting for you but you will never find her if you do not give yourself a chance and do not leave yourself open to meeting someone new. Make room in your heart for good things to happen to you.
Yes, of course, you are not ready to immediately jump into a new relationship, but you need to remember that you are a man worth loving and living with.
People who care about each other want to be near each other, spend time together - even the introverts who need their own space. You certainly can have both, a good relationship and your own space.
I could never live with someone who was constantly in my pocket - I need time and space to myself, more so than the average person.
You must honor and respect yourself and your own desires and happiness - if you do not, how can you expect others to respect and honor you?
I am not saying that you are a doormat, but I do feel like this twisting yourself into a pretzel to make this work has just backfired big time.
Think long and hard about what you want and how you want to live your life going forward - listen to your inner voice.
You've received plenty of good input - it doesn't matter that some of it may not have been said in a kind manner - it is the content of the message that you need to consider - that is why you asked, right?