A bit judgmental are you? After all HE was also having sex outside of marriage with her at the time. Had he been married maybe this would not have happened? Maybe she aborted because she thought he would dump her for being pregnant? Maybe just maybe this is why God said to wait till marriage.
It is not at all clear from the letter that he was the father of the baby. If he was, so much the worse of her. But the way it is phrased makes it sound like otherwise. If he was, then he has a right to feel betrayed.
Contrary to popular belief many men are highly distressed when their child is aborted with or without their knowledge, without their consent.