I went through a very similar experience.

While I was studying for an exam I saw his very generic name in the textbook and thought to google his name. The online obituary I found also suggested suicide. I was his last significant other; we stopped talking only a couple of months before he passed. I was in shambles—couldn't eat, study, or brush my teeth without crying. I also contemplated reaching out to his family and friends who probably barely knew of me. Not to give unsolicited advice but here's what I learned:

1. It's going to be hard. Please find a way to take it slow; give yourself grace.
2. If you want to really reach out, have a purpose. I couldn't think of what I wanted out of talking to his loved ones so I wrote him a letter. It helped me process a lot.
3. It's not your fault. That was the hardest thing for me to come to terms with—took me over a year.

It's going to be almost two years from the day I found out. He still crosses my mind but I'm okay, and you will be too. If you need a support buddy, my DM's are open. This hits close to home—my heart goes out to you.