You want him back now but is it really in your best interest? To want him back even though it brings you unhappiness? It can't possibly work because you aren't high in his priority list. You couldn't possibly be happy when you are down there. I say this because he has time to flirt with others.
So you want him back. Begging hasn't worked, nagging hasn't worked. I know you want to fight for what this is and what you care about but he doesn't feel the same way. If you both aren't fighting for something, it's a losing battle. What you should be focused on is not how to get him back, but how to relearn to live life without him. You did before you guys dated and you will afterwards. Rediscovering that you can and will be absolutely one hundred percent fine on your own. You are breathing, you are alive. I assume you are in good health and have a lot going for you. You will be fine.
The question should be "Should I delete him off facebook because it doesn't help ME out?" I don't think it's a good idea, I did that with my ex and I did that sad crawl back to refriend her. Don't burn bridges in the moment, take a look at the big picture here. I do recommend deleting him off your minifeed though so you aren't tempted to look at it and the minifeed of your mutual friends that are close to him (They will be writing shit all the time). And you have to do the best you can not to look at his profile. It takes some willpower here. When it comes to looking at it, you have to ask yourself "What's the best possible outcome of looking at his profile?" Being upset and crying, especially if there is another girl involved? Not worth it, so don't do it.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.