It sounds as if your wife felt the need to break away and have some freedom ~ first with the job, then staying out, finally moving away ~ even when she was the mother of a young baby. Did she marry very young and not realise the responsibility that she was taking on?
She left you for someone, who was not good for her, so one has to wonder why ~ especially when this also meant leaving her daughter behind. Was she seeking excitement and adventure, or just escape from the realities of life, or had she fallen out of love and just needed to leave the marriage behind?
Now there is talk of you getting back together:
Is it what she really wants, or does she say it to keep the peace?
Perhaps she does not want to feel 'trapped' as housewife and mother, again?
Perhaps she is fearful of changing things ~ she may just like everything the way that it now is?
I would have recommended relationship counselling, but you have already tried that. Counsellors cannot actually 'do' anything; they can only enable you to look at your own problems objectively, so that they may be dealt with.
If counselling didn't help, then maybe your marriage is not meant to be. Perhaps your current friendly but separate relationship might be best for all of you.
You know what you want, but what does she really want?
Have you asked her?
Have you had a serious discussion with her about all of this?
When did you have counselling?
What do you think went wrong (bearing in mind that counsellors are not there to make decisions for you)?