Is divorce or legal separation acceptable to us Christians?

You can only do your best, if the other party is unwilling to reconcile than there is nothing you can do. If God puts it on your heart than wait, if the other person has moved on and is committed to someone else than there isn't going to be a chance for reconciling. According to the scriptures the only cause for divorce is fornication. Some people say even than it only means to show who is at fault. Most important does your friend feel that its time for him to move on, whats ok for you might not be ok for him. Maybe God has put it on his heart to wait for the other person because God is trying to work things back out on his ex-wife.