TLDR: I couldn't leave my ex alone and he's ended his life

I have to get this off my chest, I'm in so much pain.

I dated the sweetest, most caring man between the ages of 18-25. He was incredibly loving but had a lot of issues in his past. He was abused as a child and his mom died when he was young. He and I clicked so deeply, we travelled to 16 countries together and grew up with each other. We even got our first apartment together.

Unfortunately his mental health put a lot of pressure on me. He was so supportive while I was in college and getting started in life but I felt trapped. He had no friends other than me, struggled to hold down a job due to his mental health but would cook for me, clean for me and take me on trips, he adored me. Eventually he got a good job and I decided it was the right time to leave him because I felt I needed to be free from 'taking care' of him so much and wanted to be with someone more stable.

As soon as we broke up he fell apart. He begged me to stay with him for months, but it just made me want to pull away more. I met someone else and started dating him. He is lovely too, and more stable, with a good job and a good social life. It felt like it would be a healthier relationship. I started dating him only 8 weeks after I split from my ex and didn't take time to process our split. Because of this I kept going back to him, just calling him or texting him. I couldn't forget all of our memories. Every time I tried to get over him I fell deeper into this anxiety that I didn't want to lose him from my life.

I also felt incredible guilt that he was in so much pain. When I thought of him desperately crying for me when I walked out of our apartment I wanted to be there for him, I had nightmares about it. Then I would phone him. But also in the good times- I saw he was going on trips without me and I'd call because I was anxious he was with someone else. I shouldn't have been going behind my boyfriend's back but I was going insane, torn between them.

This went on for three years. I never went more than three weeks without at least exchanging text messages. I was still with my boyfriend all this time and he never knew. He is so much healthier for me than my ex was but my ex was my first love and he never dated anyone else, he just held out hope all that time that we would get back together. Finally, I broke up with my boyfriend this summer and went to see my ex. We started dating again, only for a month or so. A very intense month, we couldn't leave each other alone. I slept in his bed most nights, kissing him and feeling like old times. But I started missing my boyfriend and didn't know what to do. I broke things off with my ex and went running back to my boyfriend. I was crying daily and so anxious I didn't know what to do, I went onto anti depressants.

The last time I spoke to my ex was in July, I had a phone call two weeks ago from his dad to tell me he'd overdosed. I love him so much and miss him every second. I'm constantly crying and feel so guilty.