You never really know what is going on in these circumstances and it takes a long time for both parties to sort out their lives. It is very important to keep a good relationship with your DIL so try to be kind to her. She will have lots of mixed up feelings that she does not know how to deal with.
It reminded me of something that happened years ago. The background to this is that after I left my abusive first husband he harassed the hell out of me for about a year, trying to get me back. Tried everything to get me back from badgering me into couples counselling to death threats. Upset my kids, threatened to hit my stepfather, made his mother's life miserable etc etc
About 10 years later I was at a social event. I noticed that a woman kept staring at me. After several hours she cornered me and revealed that while all that carnage was going on, he was seeing her! Met my 7 yr old son even.
She was really fascinated to meet me! Always wanted to know what I looked like etc Wanted to be my new best friend!
With the benefit of distance I found this rather entertaining. But it just goes to show that even if you are closely involved, you never know what is really going on.
Passports not in the drawer I always keep them in. Turning the place upside down.