How can I enjoy myself abroad without worrying about my ex?

2 months from now I will be living in another country. I will be volunteering, meeting new people and trying to immerse myself in a new culture for a total of 6 months. This is something I have wanted to do for a very long time.

I am leaving behind someone who I have a very complicated relationship with. He is my ex boyfriend, we haven’t been together for a year, but we are extremely close friends to the point where you may as well call it something like a ‘platonic romantic relationship’. We spend a lot of time together, have sleepovers, talk constantly, but we don’t sleep together or do anything of the sort. I am aware that this is most likely an unhealthy relationship, and that is not what I want to discuss at this time. I’m only trying to provide some background.

I love this man very much, not in a romantic way, but in the way that I feel a strong need to take care of him and make sure he is safe and happy, sometimes I feel almost maternal towards him, though I’m not sure that’s really the best way to describe it.

When I first met him, he had a lot of mental health issues, he was very sad and suicidal. I feel like I made a substantial difference in his recovery from that. Near the end of our relationship, he did not treat me well, which is ultimately why we broke up. Honestly he still doesn’t treat me well, I am a pretty co dependant person and I find myself stuck wanting to move on without him while also wanting to be in his life so that I can keep him safe (I know, not my job).

Anyways, back to the real point, I’m leaving him behind and it terrifies me. I’m worried that I’m going to miss him so much, and worry so much that I wont be able to enjoy my time away. I have an understandable but mostly irrational fear that he will get depressed again and kill himself while I’m gone. I am his only friend and I worry that without me he will be extremely lonely and unhappy.

He is totally supportive of this whole thing and says of course he will miss me but he will be fine. These fears are mostly unwarranted I think, but I cant help feeling this way and its causing me a huge amount of anxiety when I haven’t even left yet.
Basically, I’m just asking for advice.. From anyone who has been in a similar position or can imagine it. How can I overcome the fear of missing him/him dying while I’m gone?

PS: I realize how this whole thing makes me look but I swear 100% that I don’t have any romantic feelings for him, its just a messed up situation.