I was actually trying to point out that it may be harder to leave a long established marriage involving a great deal of assets and children than say your high school sweetheart. Even over infidelity.
I agree with the love factor, but I am not sure it requires marriage to validate it. I am not anti-marriage I am just being clinical

.
Timing seems to have as much to do with marriage as any great love or passion it seems also.
But I notice that some of the posts are a bit cavalier at the ease of leaving an established economic unit, children, and a deep emotional bond. Albeit one that has been betrayed.
Persnally, I can't imagine ever getting past infidelity (short of there being some kind of prior agreement). Even if I tried to forgive in the short-run I would end up despising the woman. In that case I would definitely go for custody also, regardless of how ugly that trial got.