Health, I am in a very similar situation to you, though my ex is still maintaining some level of observance, and facilitates the kids doing so. But I have come to a completely different conclusion. It seems to me the factionalism and even elitism which you or I might understand, if not justify, contrasted with the open hearts and homes of those involved in kiruv, and the longer she lived in the frum world, the less she saw of the open hearts and the more of the less savory elements of frum society. It didn’t have a good hashpo’oh on her, and real problems can’t be conveniently explained away.
I believe in kol yisroel areivim ze bazeh means each and every Jew, and we cant pick and choose who we are going to “allow” to take on one, ten, or all mitzvos – because choosing to help or facilitate observance is in practical terms choosing to allow or not.