My wife could have written this. Like you and your husband, we got together around age 50 after both of us had previous marriages. Like your husband, I am not the father or grandfather. None of the kids or grandkids dislike me, but I have nothing to contribute when they are reminiscing about the old days, and I am slow to discipline any of the grandchildren. There is a degree of separateness I will never be able to bridge. They're mine, but they're not mine. And I am sure my wife feels just like you. No one ever better make her choose, least of all me.