My ex left me when I was four months pregnant with his kid, I never heard from him again. I still have a soft spot for him, and no hard feelings. I can't really explain it, he just touched my heart in such a way that after the initial hurt it didn't seem to matter anymore.
I'm very anti-divorce with kids still at home, divorce is hard for kids, but by old age it seems silly to waste time with someone who doesn't add anything to your life. At the same time, the prospect of motherhood can definitely make a pointless marriage feel worthwhile. But if the kid gets involved there may be more pressure to stay married to your husband, which could be the opposite of what you want. What a tough situation. Hope it works out well for you.