I just cant shake the feeling that I should do something tomorrow, but I'm conflicted . If I dont get in touch, what if he does what he threatened to do?
PLEASE don't do anything. If the day means something to both of you he may well be expecting you to get in touch in some way which is him reeling you in, although it'll be seen as your choice. Same if it means something to him alone. If it means something to you alone it's irrelevant to him.
If he chooses to harm himself in any way, it is his choice and nothing to do with you. You are not to blame for any of it. These people always blame other people for everything. They are always the victim. No matter how much abuse they dole out, it is never their fault.
PLEASE DO NOT CONTACT HIM, for your own sake 
I can honestly say that I dont even feel any relief that hes gone
It took me a long time to feel the relief. As soon as he had left the house it felt calmer and the stress starting lifting already but it was a good few weeks, maybe even two or three months, till I actually felt what I could properly identify as relief. And when it hit, the joy I felt was amazing. I still smile to myself when I'm doing something MY way. I always thought I was reasonably happy before (not while the worst of the abuse was going on, obviously) but now I know what real happiness is 
Keep reaching out to anyone who can help, keep posting on here. If you feel like contacting him, wait for half an hour before you make any firm decisions but please, do not contact him. The way you're feeling now? It'll be ten times as bad if you take any backward steps so keep going forwards, lovely 