I have raised our 4 year old son (he calls me mom) since he was a few months old.. bio mom was homeless/on drugs and CPS got involved. The father and I got together and we have had full legal and physical custody, mom has 3 visits/year. She has missed almost every one of her visits over the years, and even disappeared last year for the entire year w/no contact at all. She showed up this year with a new baby, a new boyfriend and a brand new attitude. She told me she wanted to "be a good mom to her kids" and that she's ready to "step in as the parent now", basically telling me that I was not needed in "her" son's life anymore. My son literally has no idea who she is because she has never called him and has only seen him a handful of times since we got custody over 3 years ago. She still doesn't have a job, no vehicle, and she is staying with a friend. She also hasn't done any of the anger management/rehab classes the judge ordered her to do years ago. But somehow she told us she is filing for custody.. She texted my SO telling him that I'm "playing mommy" and that no b**** can take her place, etc. she even called him to tell him what a POS I am and that I'm a fat pig, blah blah. My SO stood up for me, but it still hurt. I was pissed she has not made ANY effort to see her son, and now after 3 years she decides that she wants to "step in"?! No lady, I stepped up, stepped in, and I'm not going anywhere. I have never been rude to her b/c I don't ever want the little guy to think I'm against his bio mom. What frustrates me the most is now my SO says he feels bad for the bio mom missing out on the kid's life, and he is willing to do 50/50, he says "mostly because of the new baby".. he wants our son to get to know his new brother. I am totally for him knowing his brother, but I know the bio mom: the second she gets mad at us she will rip away her baby from seeing his older brother, just to punish us. It will hurt the kids though, not us. What should I do? If she did her court-ordered classes and made an effort to call her first-born son, I would be more open to getting the kids together/seeing her more etc. but she is just too unpredictable, and I just want to protect my son until he is old enough to understand. I need advice 😔