I dont think you should feel guilty at all. It doesnt sound like you did anything wrong.. infact you were completely honest with her on every occasion, you didnt seem to be concealing anything.. sometimes people are just jealous and you cant really do much about it , i dont think you acting any different would have effected anything, the situation her mother went through definitely had an effect on her as well, probably causing her to feel more vulnerable in a relationship because she saw the harshness of the world at such a young age. I just think it would have been better if you wouldve communicated with her more, but the past is the past and you have to move on , so dont feel guilt 🙂 have a good day