The 40-year-old actor and the former 'Doctor Who' star were granted a quickie divorce in December 2016, but it was only last month the former couple ended an intense two-year legal battle for their two children - Winston, nine, and Eugene, six - which left Laurence with insomnia and panic attacks at the thought of losing access to his kids.
He told the Mail on Sunday newspaper: ''I was certainly in a very dark place at one point -- at my lowest ebb.
''I almost felt like I couldn't go on. It all felt so hopeless.
''I understand why some men feel so hopeless they commit suicide and find themselves lying on the train tracks.
''The emotional strain was dreadful. For six months I found it hard to sleep.
''Fortunately, I have the greatest friends in the world and the most wonderful family. Just the thought of my gorgeous kids made me realise there was a life to be lived.''
The former 'Lewis' star was forced to remortgage his house due to the hefty legal feels, but he doesn't blame the former pop star for his predicament and has instead called for the ''flawed'' divorce system not to point the finger at individuals.
He is now thankful he gets to be with his children and even spent Father's Day (17.06.18) with them at his home.
He added: ''With divorce, you immediately lose half the time you'd spend with the kids. That in itself is a mental health crisis. But, like everything, these feelings pass and you start to feel stronger with every day.''
Though Laurence and Billie - who was previously married to DJ Chris Evans - didn't split until 2016, the 'Whatever Love Means' actor admitted they had spent ''years'' in a bad place and he's ''thrilled'' they are no longer together.
He said: ''I've got lots of nice things to say about Billie but I'm thrilled our marriage ended - it was a bad marriage. It took us years to get from 'we're not happy' to 'let's get divorced'.
We went to marriage counselling. In the end, it finished fast - the tone of text messages between us changed in days.''
However, he insists he has no ''regrets'' about their relationship and he has nothing but good wishes for his ex-wife.
He added: ''But I don't regret any of it - I sat in a hospital room while she had Winston by emergency caesarean and it doesn't get any more real than that.
''My kids need her as much as they need me. I wish her, as I've always wished her, love and support in everything she does.
''I hope she's the best she can be as a mother and as an actress. I'd never want to stop Billie being the mother she is to the kids.''
From 'Happy' to 'Banana Pancakes', these are soaked in positivity.