Catholic dating divorced person
I'm not as concerned about why she got a divorce. As far as I can tell:(1) If we presume that their marriage is valid (and I think we are supposed to), then you are not permitted to do anything with them that you would not be permitted to do with any other married person.(2) You cannot date a married person.
Conclusion: you cannot date the divorced Protestant.
This means that the former spouses are still deemed married while the Tribunal investigates to determine whether there was a sacramental marriage.
Since it is clear that it is not morally acceptable for a married spouse to date, former spouses who are still deemed married would have to wait to begin dating until they receive the ordinary process annulment.
Since they are Catholic they can't really undergo the annulment process because they don't believe in it yah know?
So it's not your soul in danger in that regard, but rather theirs.
If you know him well enough to consider beginning a romantic, marriage-minded relationship, you should be able to explain the situation to him and assess his willingness to seek a declaration of nullity. I'll just keep considering her an old friend, and she'd have to get an annulment if we ever want that to change. It would be a good idea to ask your priest or another neutral moral theologian who has studied the law and morality.
You are not breaking their marriage or your own vows.