@FredFriendly Bah. He's in love with her, has been for a while. She was going on and on about how she's a miserable person, how nobody should love her, and her unknown email exchange partner also must be just pitying her. He simply couldn't keep listening to it, seeing how he considers her a good girl worthy of loving. Earlier in the chapter I got a feeling he wouldn't confess in this chapter, not so soon after what she went through, but when she kept badmouthing herself, I thought he needs to do it now. Who knows what she might otherwise do to herself. He needed to let her know she's just fine. This was most certainly the most effective way of doing it, especially since it was honest, not some empty platitudes.
In addition to that, she also needs to forget the unknown person as soon as possible, for her own good. This, if anything, ought to help her do it.
You know, romantic love is always half selfish. If his timing was selfish, then it was. Can't be helped.