How did you meet people who had been through similar experiences, are there support groups or something like that?
I haven't met anybody that went through 'Spousal Abandonment' in rl. To find the answers and support I trawled the Internet.
Here are some links I found helpful:
Lisa Arends wrote a book about it and she's on Facebook:
https://lessonsfromtheendofamarriage.com/i-feel-alone-divorce/
Vicky Stark has also written a book about it:
https://www.runawayhusbands.com
Chumplady is good regarding Infidelity but I don't know if your partner has cheated? She's also written a book:
https://www.chumplady.com
I'm 5 weeks into it and I'm very depressed now
Yes perfectly understandable. Have a look at The Change Curve:
https://www.google.co.uk/amp/s/www.psychologytoday.com/blog/me-we/201406/the-7-stages-grieving-breakup%3famp
I'm off work cos I can't face it
It's good you're off work and maybe you could use this time to plan little walks and be outside in nature?
....and like you say feel humiliated by the pity and the people laughing at me.
Why do you think people are laughing at you? Marriages end all the time, have you seen how hight the statistics are?
https://www.google.co.uk/amp/www.independent.co.uk/life-style/love-sex/the-nine-most-common-reasons-couples-get-divorce-a6875356.html%3famp
I just don't know how to heal.
Slowly, in your own time, read the above.
What is a codependent?
There is a lot of info on the net about it but here's a link to get you started:
https://www.webmd.com/sex-relationships/features/signs-of-a-codependent-relationship
I wonder if this is me too?
Who knows but knowledge is power. I'm a codependent but I'm also a work in progress....
These links might help you work out what went wrong?
John Gottman, his credentials:
https://en.m.wikipedia.org/wiki/JohnGottmann__
One of his many books:
Why Marriages Succeed or Fail https://www.amazon.co.uk/dp/0747593604/ref=cmm_swrrcpapii_-tYIAb1XD1FEH
The 4 Horsemen of The Apocalypse:
https://www.gottman.com/blog/the-four-horsemen-recognizing-criticism-contempt-defensiveness-and-stonewalling/
I hope this helps 