34 weeks pregnant and realizing my relationship may be over. I'm not sure what to do.

Apologies in advance for the length of this. I know this is partly venting, but I would really appreciate any advice.

I (18F) am currently 34 weeks pregnant with my boyfriend's (20M) baby. We've been together for almost four years. The pregnancy wasn't planned—I had an IUD and we were using condoms most of the time.

For some background, we broke up for about seven months after I was struggling with severe mental health issues and was hospitalized following a suicide attempt. I ended the relationship because I genuinely believed he would be better off without me. Looking back, I know how much that hurt him, and I've apologized for it. We eventually reconnected after the relationship he started during our breakup ended.

The problem is that he hasn't been the same since we got back together. Before we broke up, he was incredibly kind and attentive. He bought me flowers, made me feel loved, and I truly believed he would have done anything for me. I think a big part of why I've stayed is because I keep hoping that version of him will come back, but I honestly haven't seen him in a long time.

Even before I got pregnant, he had become emotionally distant. I hate admitting this, but sometimes I only wanted to have sex because it was the only time I felt close to him or important to him. Around that time, I also found old messages from when we were broken up where he was saying incredibly hurtful things about me. He sent pictures zoomed in on my self-harm scars to his friends, called me a "crazy pathetic bitch," and even told his ex about deeply personal childhood trauma that I had trusted him with, saying he could understand why my birth parents abandoned me.

When I found out I was pregnant, I called him immediately because I needed support. Instead, he basically told me we'd talk later, hung up, and went to the gym with his friend. I tried to tell myself he was just overwhelmed, but I felt completely alone.

Things have only gotten worse throughout my pregnancy. He rarely comes to see me anymore, and when he does, he mostly sits on his phone unless he wants sex. Afterwards, he goes right back to scrolling. He stopped doing all the little things that used to make me feel loved, and while I know flowers aren't the important issue here, it hurt realizing he had completely stopped putting effort into our relationship. One time he even asked me for gas money just to drive 20 minutes to see me, which was completely unlike him.

We've been arguing much more, and during one argument he threatened to go for full custody of our son because I'm "unstable." His mom works in the court system in our small town, and whether that's a realistic concern or not, it terrified me. I have never wanted to keep our son from having a relationship with his father. I just don't want my mental health history used against me.

There have been other things too. He invited a girl he used to talk to romantically to our baby shower without even asking me. While I was opening gifts, he spent time talking to her while I was trying not to cry. It was supposed to be a happy day for us, and instead I felt humiliated.

His mom has also become very involved in the pregnancy in ways that make me uncomfortable. She calls my baby "her baby," has tried to influence what we name him, and has pushed to be in the delivery room. It makes me worry that if we ever split up, she'll encourage him to fight me for custody or try to make my son think I'm the bad parent.

Right now, the plan is for me and the baby to move into an addition they're building onto his family's house after my six-week postpartum recovery. Part of me thinks that's a terrible idea, but I'm scared of what happens if I don't. I'm terrified that if I leave, he'll try to take my baby from me.

I also know a lot of people will probably tell me to leave. Maybe they're right. I just don't know how to find the courage to do it when I'm so scared of losing time with my son. I'm also scared that, as an 18-year-old single mom, no one will ever want me again. I know that probably sounds irrational, but it's a fear I have.

If you've been in a similar situation, I'd really appreciate any advice. How do you know when it's time to leave? How can I protect myself if custody ever becomes an issue? Has anyone had a baby young, left an unhealthy relationship, and eventually found happiness and love again?

Thank you so much if you read all of this. I really appreciate it.