This was totally unexpected. BM has made both DH and my life hell for the last 5 years (since we started dating). Dragging us to court, parental alienation, cussing out DH on the regular, etc. etc. Typical HCBM behavior. I disengaged from her from the start, never wanting a conversation with her or even meeting in person. Within the past year, DH had only talked to her via text to have everything in writing and to also keep it strictly to SD. 

Well yesterday DH received a text "I just sent ____ a message on Facebook, btw, incase she wants to read it." DH goes "DId you get something from ______" Joking, but half serious since it's happened before, I said "What, a death threat?" Also, I thought we blocked each other on FB?

Well, I guess she had unblocked and I indeed did get a message. She went on to APOLOGIZE for the last few years for "all the trouble she's caused." SD is struggling BADLY in school (I'm a teacher) and she went on to say she's sorry for not acknowledging all of my work to help DH raise her. And "promised" it wouldn't go unnoticed anymore. Her excuse for the past few years was "she was in a bad place" and BF at the time was on drugs. Honestly, I'm assuming she was too. But that's a different issue. 

DH and I both have assumed she has boderline personality disorder or bipolar. She goes on these "highs" (about every 6 months or so, or when she gets a new boyfriend) and attempts to be cordial again. BM did say she does not expect us to be friends, but wanted to apologize. But, GAVE ME HER NUMBER, if something came up with school. 

I'm extremely cautious. She always has a MO. Is she REALLY seeing the light this time? Is she grasping at straws because DH and I are finally having an "ours" baby and she doesn't want to lose attention? 

I'm not going to put anything in writing to BM. I don't plan on calling her about school either. DH can continue to do the communicating. What do you guys think? Any insight as what you think her true intentions are?