10+ years is a pretty long time and I'm sure they see relationships that dissolve much quicker all the time. However, did the spouse just recently become a citizen (if so, that may be more concerning)? Also, the whole meeting another individual and having a child together while still being married to current spouse I'm sure will raise an eyebrow.
That said, is the United States completely out of potential spouses? I have been married to my spouse going on 15 years now and, God forbid something ever happened to our relationship, but I would NEVER EVER do the immigration thing again; too much work, too much stress, and too much money.