I had enough already (hence my username) and divorced a man very similar to yours. Gambling, among other things, helped destroy our family. I could no longer trust him, he wouldn't allow me to handle all finances, I didn't want to have to treat him like a child, and I didn't want to therefore enable his gambling and support him forever on my salary, which is what it felt like and what it in fact was, as he seemed to think his wage was his alone to play around with while mine was essentially paying all the bills. I couldn't face retirement knowing he could waste all "our" money. I lost respect for him and I couldn't stay. I couldn't let my children think it was ok that dad was gone all hourseither gambling or napping at home and wasn't a true coparent.
Within a year of being divorced, my finances had bounced back, even with renting an apartment (USA). I did not want the house or to be a homeowner on my own. We had actually refinanced our mortgage to pay credit card debt, which had built up due to his gambling. Such a temporary fix.
He always thought he was such a great money guy, so full of advice for other people. He sat on the finance committee of our church and I thought "if they only knew".
Knowing you are the higher earner, if you do leave, just know you will probably have to pay him (I did here in US), a formula of wages and time spent with each parent is calculated. Even with my rent and having to pay him, I still feel it was worth it. I no longer worry Every Single Day where he is, what he is doing, if he is spending money gambling.
Divorcing itself was not that difficult except I'm such an introvert that it all seemed overwhelming. My lawyer helped me with the best advice, that the whole process is not done all at once, but in nice little chunks of tasks to be done. She was right, and I got through it.
The fact that your child is now in school really does help your situation. If you choose to leave, it will be easier to retain your job and to coparent.
Best of luck to you, whatever you decide.