I don't want to minimise your hurt and sense of betrayal. But...is it worth taking a step back, from his actions and your emotions about them, and considering whether it is worthwhile NOT pushing everything over the cliff-edge right now? I just looked up Lucy Wadham, who as an Englishwoman married to a French man, and living in France for 25 years, became used to a different way of approaching these questions of fidelity, full transparency as opposed to the values of 'discretion':
When I first moved to Paris 25 years ago to be with my French husband,
I discovered a world in which infidelity was accepted as an occupational hazard of marriage. The general view was that discretion was essential, fidelity less so. All around us, couples old and young seemed to be managing their infidelities. I learned quickly that my view of marriage as a constant quest for transparency was seen either as delusional or as a recipe for divorce. In some ways, I am living proof of this idea: my faithful marriage broke up after 15 years while the many unfaithful ones around us are still going strong.
Look, this may not be for you. But previous posters have said that they managed to get past infidelity in their marriage, and I'm fairly certain that I would get past it in mine - if it weren't, of course, accompanied by neglect and abuse, or diminishing of mutual respect in other ways - our role as parents, as financial partners, as a team supporting each other in our ambitions, work, commitments and pleasures. Only you can know
whether you can keep on in your marriage on such terms, but it might be worth considering rather than pressing the divorce button, which often makes people and families poorer and more fragile.