I suggest doing a tag search on "foundations" and "lessons" too. Both of you could use some grounding and balance it seems. You've been through a lot.
I suggest being monogamous for a while and working on your game plan. Do some things together towards building trust and a foundation with boundaries that work for you both. Some councelling from a poly friendly councellor might help with making sure you both are treating each other respectfully and are not abusing each other due to self esteem issues.
Once there is some confidence, trust and self esteem built you could then start dating each other again. I say each other because it sounds like your relationship really didn't start out well. Starting again and building up a romance again might help you both feel more connected and therefore more confident in what you have.
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