That's between you and your boss.
I'm sorry to hear that you are hurting, but every company is different and every boss is different. I understand that you are grieving, but most workplaces make no concession for that beyond a death in the immediate family. Many companies now grant Personal Time Off (PTO), a set number of days each year for you to use as you choose: sick days, vacation, funerals, nursing a hangover, whatever. If that's your company's policy, your boss might let you take a PTO day today, but again, that's between you and him.
My advice: unless you're a blubbering mess, stay at work. Being around other people will take your mind off your troubles, and it beats sitting in a dark apartment crying alone. Also, a few months from now you'll be pissed that you blew a PTO day on your ex. So suck it up--the day's more than half over, anyway.
Hang in there, and thanks for the question.
Whatever you do, Hurting, don't wallow in pain on your own. As someone who's been there, stay busy ...even if it is at work. The busier you are the less time you'll have to think about it and indulge the sorrow, the hurt, the anger etc. Surround yourself with good friends and tell them that you need support and encouragement right now because you're struggling with a loss, but that you want them to be vigilant and keep tabs on you so that you're NOT sitting at home alone crying about it.
I know that it's important to go through the stages of grief when you "let go" of someone you care for but keep in mind that it's also uber important that you start looking out for yourself and start tending to your own needs. Often when we're a part of a duo, our own personal needs fall to the wayside so now that you're flying solo it's a good time to start getting reacquainted with yourself and start pursuing things (hobbies/interests) that have intrigued you.
The more you get out there -- keeping busy -- adjusting and learning to have fun again while pursuing things that bring you some measure of joy, the more you'll have to offer the right person when they come along. Think of it as one of the greatest personal investments you'll ever make. In my case, my friends were honestly my life savers -- they just refused to let me sit alone in the dark licking my wounds. Suffice it to say, a few months down the road when I was ready to open my heart again -- it was to someone I considered a good friend who also happened to watch me evolve post-breakup. Just goes to show you that you never know what life has in store for you down the road... chin up and best of luck, hon.
I'm going through the same problem.. only difference is I work with the guy. We work in different departments but I still see him all the time. How am I supposed to get over a guy that I see at work? I'm ok until I see him and then I can't stop thinking about him....I'm totally in love with him, and I'm beside myself because I've NEVER had a problem walking away from anyone if I wasn't happy.....
Did you miss the umpteen posts on whether or not someone should get involved with someone else at work and the advisability thereof? Sigh......... Now you know why NOT to. Sucks big time. Been there, didn't pay attention to the memo myself. But I'll tell you, once I did start listening up, the sheer number of bullets I dodged later on... oh, my.