Hello Emily, can we offer you a warm welcome and under the predicament you're in, the marriage is between you and your husband and not his mother and himself.
He is not entitled to raise his voice, swear and name call you, just because he would have his mother's support, this is not how a marriage should function.
I can't tell you what to do, what pulling away from him over the last 5 years is an indication, and if you stay together and have children, then it's likely she will be telling your children exactly what you have been trying for them not to do and when they return home, it's another struggle you have to contend with.
It all depends on what you want to forgive her about, you raise the children as best as you see fit and the world has changed since his mother was raising him, although the basic rules still apply, but as the kids grow up the grandparents become older, just as I am, the parents have their own rules and what the kids are allowed to do as they begin to mature.
Hope to hear back from you.