I sort of get the feeling, purely my own feeling, that when she went to Ireland, she was running away. We know she posted on Yahoo, sometime after November 2006 & presumably before went to Ireland in April 2008, about her 8 year old stepdaughter as she put it then. She said in her post that she loved her very much. I just have this feeling that something went wrong and she ran away to Ireland to escape.
When she got involved with Jason's children, she in turn got involved with Jason and he was not going to stand in her way of keeping those children. Her obsession also appears to be with the little girl rather than both children which in itself is very sad and I would hope that Jason's son never hears of it. As to whether she can have children of her own, I have no idea and personally would not wish to speculate on it. Of course it could be a reason as to why she attached herself to other children but adoption could also be an option if needed. IMO her obsession was with a ready made family, once she was attached, she was not letting go. I would hope that they have tracked down the father of the child she referred to earlier as her 8 year old stepdaughter, I suspect that he has a story to tell.