I just don’t feel ready to lose him in my life as my friend but I know it’s the healthy thing to do
I've got an ex who's a friend. A couple of my friends have exes as friends. A couple I know were introduced to each other by one of their exes! All happy people. There's no reason you should lose him forever.
Also: You've done heartbreak before. You know that you, personally, can feel fine once you've recovered. How do you feel now when you think of the previous ex? Still ripped to shreds, or something far easier to live with?
Also: Can you remember before you met him? Before he was part of your life? Were you a seething emotional wreck, when he wasn't in your life? Or were you... ok, actually? It's perfectly possible to live without him and be fine. You've done it before.
Also: Google single celebrities. You'll feel better once you know you're in the company of Halle Berry and Charlize Theron.
Also: it just feels like I have thing to look forward to anymore Give yourself full permission to feel like this. It's fine. It's what's meant to happen. You have a swamp of emotion to wade through, and it's bloody hard work. Accept that it's hard, and treat yourself like a person you love, who's doing endless hours in a job they hate. Be lovely to yourself. Ice cream, duvet days, binge watching box sets. It's fine. You're allowed to feel like crap, and there's no pressure to feel good or 'get a life'. You're great in your slippers and pjs.
Also: Wait. Quietly wait in the pond of tears you're in, and one day, not too far away, the season will change, and the pond will dry up and there'll be blossom. But for now, you're in the pits of winter, snowed in, and it's impossible to imagine summer BBQs in sleeveless tops. It'll come. You only have to quietly wait.