Should I make our trial separation a permanent one?

I'm currently having a trial separation from my husband, and feel calm and happy for the first time in years, despite having two young children to look after.

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We had been having relationship counselling in an effort to save the marriage, but it wasn't working as he refused to be honest and to take responsibility for his side of things. Basically, he still acts like a teenager and when I try to encourage him to talk or help out with the kids, he accuses me of being a nag and trying to stifle him. He's so immature.

He is not enjoying the trial separation - probably because he's at his mate's house and has no one to run around after him - and keeps saying he misses me and wants to change.