My dear friend, I dont know why she has been behaving the way she has in the past. People do all sorts of things for various reasons and in this case my main concern is you as a valued member of this site and the one who has been going though these issues.

From what you say, your intution has never betrayed you in this situation and still does not. Do not torture youself with why she did this and why she behaved that way. Moreover, you should not kick yourself for not being this way or that way towards her. This relationship was probably never going to work and with sadness I tell you now to accept the present and try to move on.

You may be probably be right that she was trying to find a safe haven for herself and children and if she has found that elsewhere, wish her all the best and let go.

Blessings to you my dear friend.