This issue still needs a lot of discussion especially religion plays a large role. But as I observed there are many couples and children suffered because of failed marriage. If the marriage became toxic to the point that it affects the whole family negatively, is it not enough end the marriage? Because that is what exactly happened in my sister's marriage. Her husband cheated on her not just once but multiple times, he's also irresponsible husband and to be honest I have a lot more to say about him but I think I should keep it private. 

Set them free and let them open their hearts for someone they deserve.