Not right for him?

My husband and I are an interracial, international, intercultural, interfaith couple with a relatively large age difference. Statistically, our marriage is doomed for failure. But the truth is, we are very happy together--for the most part. Yesterday my husband admitted that he is frustrated that I don't feel comfortable with his religion, and embarrassed to take me into religious situations. I hate to make him ashamed of me, but I can't really change that part of who I am. Otherwise, he seems to be satisfied with me as a wife. And if we never have kids, I'm confident we would be happy "til death do us part." But that's the thing. Even before I met my husband, the thought of having kids terrified me. Now I really dread the thought of having kids, and trying to raise them in such a way that they don't feel any tension because of their polar opposite parents. My husband, though, can't stop dreaming about the day he will become a dad.

....So my question is, should I quietly slip out of this marriage so that he can find the woman he was perhaps meant to be with? Would that be the best thing for him in the long run, or is that just selfish of me?

I know everyone will say I should have thought about this before we got married, and I did. I told him many times that the best thing for him to do would be to marry a girl from his own country. We even broke off the relationship several times. But we were in love, and we didn't want to live without each other. And we are still happy with each other, but the reality of children has set in. He's not getting any younger, and soon he will want to become a father.