Do you want a relationship that you don't have to hide?
If, on the other hand, he runs her down and blames the failure of the marriage solely on her you need to be extremely careful. It is best to avoid the situation altogether if possible, but if you find yourself in this predicament, you are not alone.
People love scandal and gossip, and a secret is only a secret when only one person knows about it.
Many, even close friends, will judge you harshly for dating a married man, so be extremely cautious about whom you discuss your situation with.
Until he files for divorce, a woman in this predicament would be wise to continue to date single and available men concurrently.
, but if you simply can't, don't limit yourself to being his woman on the side, continue to investigate other relationship options.