You are certainly entitled to sue the facility, but I think that you'll have a very difficult time winning unless you can prove to the court exactly
what happened to your fiancee. You'll need to do that so that you can show that the facility did something wrong. Otherwise, it's just speculation. For example, although this is not likely the case, it's possible that your fiancee simply reflected on her relationship with you and the kids, and decided on her own that she wanted a different life when she got out. After all, she is a grown adult and certainly has the right to make that choice. I'm not saying that's what happened, but the point is that it's a possibility, and therefore, in order to win a lawsuit, it's not enough to simply show the court that your fiancee left you and the kids. You must show that something happened for which the facility is liable.
Does that make sense?
Accordingly, before you think about taking any action against the facility, you need to discover exactly what happened in there. You can ask your fiancee, the facility itself, or even the guy that she is waiting for. Perhaps the facility will have something to say about it since it sounds like your fiancee spent time with the guy under their watch. Did they notice anything unusual? If they admit that they did, then that may be an indication that the facility did something wrong, and it may lead to a successful case. So, the bot***** *****ne is that you need to do a little investigating.
After you figure out the details, then you should retain a local attorney, as this would not be a simple small claims
"Judge Judy" type of lawsuit. This would be a rather complicated case that will require expert witnesses to establish exactly what the facility did wrong and what it should have done instead.
Does that answer your question? Please let me know if you need clarification, as I am happy to continue helping you until you are satisfied.