Hi Lea I am sorry as I have not read all your story I am just going to throw something out there for you to consider
lets say this woman really loves your sons... what is the problem in letting her show it
she will never be their mother
I am the psuedo step-mother to C's daughter his ex-wife HATES me (I had nothing to do with their marriage or break up as she cheated on him and did drugs and left him and their daughter) anyway she hates me she blasts me on facebook accuses me of everything under the sun (the latest but not worst is that I only make food from a box...yes she said it in court) she won't let me talk to her teachers (long story as to why she has A right now...sufficed to say it won't be long) or speak to her on the phone (she hangs up the phone is she hears her talking to me)
all I have done is love A
Your place is secure, your boys know who their mom is
I have learned that it is our own insecurities and hang-ups that get us in the end and if she is giving half as much time to thinking about you as you are to thinking about her, their relationship won't last very long