I'm still in love with my ex after 3 months of being apart
Why do you think you're still in love with them?
I'm never going to be okay without him as long as I live
You should do your best to try and move on from any past relationships. You left that relationship for a reason and you should remember that reason.
It's been hard as hell.
This is understandable, but you need to find things to distract you instead of dwelling on it.