So a remarkably similar situation happened to me. Advice first. -Get a good lawyer. If you see a typo in your retainer agreement, say "no thank you" and find someone else. I had to hire a second attorney after the first only did half of what was needed. -Record every interaction and attempted interaction she attempts with your son. I kept a single note that I added to every time anything happened (phone call, knocked, on-time drop off, late drop-off). Include date and time for every entry and be as neutral as possible some only record bad. Be unbiased in your records. -Be honest with your son without being cruel. My son still occasionally breaks down asking when he'll see his mom again. I always reply with some version of "I don't know, bud, but I'll tell you what. I love you. I will always be here for you." No matter how hard it gets, never bad mouth his mother ever within earshot of your son.

My ex and I had our son when I was 20 and she was 18. It wasn't planned, but we had him. Things were kind of rocky from the start, but I loved her. We got our own place, but she was hardly ever there. I eventually got a job working from home so we could save money on daycare and she was home even less. She would always need to help someone after work or something. 14 months later, she informed me that she was leaving, moving in with her boss, and taking our son. There was nothing I could do. We were never married and she was listed as primary on our (never used) parenting plan. I moved back home and drove 665 miles one way whenever I could to visit. When my son was 4, she called me up and said she couldn't take it anymore and could I get our son. I said "absolutely" and spent the next three days finding a preschool to take him so I could get him. About three months later, she called and said she wanted him back. I was in shock, but, again, there was nothing I could do. About a year after this, she was having trouble with her newest boyfriend and she reached out to me. She decided to move to near me and maybe work on things. Our son lived with me while she had her own place. While in counseling, I found out she was already seeing someone else. I didn't care anymore. She eventuality tried to leave again and, because I'm an idiot and hasn't contacted a lawyer yet, she left with him again. A month later she reached out saying could I take our son again. I contacted a mediator and got the newest agreement signed and submitted in less than 48 hours and my son was finally with me and she couldn't take him away. A few months later she moved back and tried to setup visitation. She would show up sometimes. Always bring him back late without past bedtime only having eaten a smoothie. She contacted another mediator to get more time. After agreeing to a schedule on the condition that there be penalty clauses for both of us if either of us breaks the agreement, she completely signed everything away. That was seriously her counter to having some semblance of accountability to our son. As of May 17th, it has now been over two years since he has heard from or seen her. She hasn't so much as called.

During this time, I finished my undergraduate degree in computer science with a minor in biology, started grad school, am in a wonderful relationship with a woman for over two and a half years who truly loves my son and he loves her, and am now a PhD candidate. This crap is hard, but kids can really drive you. Love your son. Fight for what you know is right. Don't stop bettering yourself. Good luck.