I do consider real abuse to be a form of abandonment. If abandonment is putting distance between yourself and your spouse, then abuse is forcing your spouse to a great distance.
I disagree that emotional abuse is somehow not as bad as physical abuse. Physical abuse is more immediately dangerous the physical well-being of the abused spouse, but emotional abuse absolutely cuts the heart. I don't have the stats currently at fingertip, but emotional abuse is more an indicator of an impending divorce than is physical abuse.
Emotional abuse is one partner demonstrating his/her contempt for the other. It is a deadly, poisonous environment, and unless healed, the only way to deal with it and maintain one's sanity is to put distance between the two parties.
The issue of abuse, whether physical or emotional, is no doubt a difficult pastoral issue. If the abusive spouse is a non-believer, then the case to be made for abandonment would be more directly relevant as such would constitute a Biblical grounds for the divorce. In the case of a believing spouse though it would seem to be much more complex. I'm inclined to agree with the previous poster regarding separation as opposed to divorce.
I would have to disagree that abandonment and abuse are the same things (regardless of the type of abuse). Jesus did not mention any kind of abuse in regards to divorce and abuse does not always put a great distance between the two spouses (not condoning it or saying it is not a big deal, just noting from my experience working with troubled families), not any more distance than other things like irresponsible spending, disagreements over raising kids, being unequally yoked, etc.