The 'Beverly Hills, 90210' star confirmed last week that the couple - who married in 2010 - had decided to go their separate ways after a decade-long on/off relationship, and he says the 34-year-old actress revealed she felt ''more like [herself]'' when she was away from him.
He explained: ''She said, 'You know, I realised while I was out of the country working alone that I feel more like myself, and I liked myself better during that experience, and I think that may be something worth trying for me.' ''
Brian - who has three sons, Noah, seven, Bodhi, six, and Journey, three with Megan - admitted he was left ''shocked'' and ''upset'' about the 'Transformers' star's revelations.
Speaking on his '...with Brian Austin Green' podcast, he said: ''I was shocked and I was upset about it, but I can't be upset at her, and I wasn't upset at her because that's ... she didn't ask to feel that way, it wasn't a choice she made, that's the way she honestly felt.''
Last week, Brian confirmed his and Megan's split, and admitted she had ''always been honest with me''.
He said: ''I wanted everyone to hear everything from me, and this is it. Neither one of us did anything to each other. She's always been honest with me. I've always been honest with her. We've had an amazing relationship. I will always love her. And I know she will always love me and I know as far as a family what we have built is really cool and really special.''
And the star vowed that he and Megan will remain good friends and co-parent well for the sake of their three kids.
He added: ''We will still do family vacations and holidays as a family and really make that a focus for the kids. It sucks when life changes and something that you're used to, that you've been doing for 15 years, you try and not get rid of but you change. There's the unknown aspect ... there's that pit in my stomach. I really don't want Megan and I to be at odds ... she's been my best friend for 15 years and I don't want to lose that.''
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