Deb,
When I read your question, I thought of the passage below. To answer your question though, I would not rule out dating her, provided the following took place.
1. She has tried to get back together with her husband. This includes waiting for a while (a couple months maybe) so he's hopefully not as angry and misses her more.
2. She has been single for a while, like a couple of years. This gives her husband longer to take her back, and gives her time to get closer to God and grow as a Christian.
3. We both feel that a relationship with each other is what God is leading us to do.
Verse from 1 Corinthians, chapter 7:
10 To the married I give this command (not I, but the Lord): A wife must not separate from her husband.
11 But if she does, she must remain unmarried or else be reconciled to her husband. And a husband must not divorce his wife.
12 To the rest I say this (I, not the Lord): If any brother has a wife who is not a believer and she is willing to live with him, he must not divorce her.
13 And if a woman has a husband who is not a believer and he is willing to live with her, she must not divorce him.
14 For the unbelieving husband has been sanctified through his wife, and the unbelieving wife has been sanctified through her believing husband. Otherwise your children would be unclean, but as it is, they are holy.
15 But if the unbeliever leaves, let him do so. A believing man or woman is not bound in such circumstances; God has called us to live in peace.
16 How do you know, wife, whether you will save your husband? Or, how do you know, husband, whether you will save your wife?
God bless and help your friend!
- Topher