If you've admitted you can't be together, then I guess you won't be, and so it's just better to move on as it can get even more toxic for the reason you've stated. How you move on is personal and no one can give you a step by step manual for that, it's based on your own instincts if that makes any sense. You can still be friends, if you can cope, but that might just make you more inclined to give in to them. I sympathise, but I also think you should just not think about relationships for now, don't feel pressurised into getting into one just because you couldn't with 'them'. You'll know when you've found 'the one'. Lol that got cheesy but just wait and see how things unfold.