Sometimes a 10 year age difference matters. At 37, you’re ready for something permanent. At 27, it sounds to me like your boyfriend isn’t ready to settle down – kids or no kids. You are his first serious relationship. It’s very possible that he doesn’t want to hurt you but wants to experience more before he chooses a life partner. Seeing each other at work all the time doesn’t help either one of you separate. The fact that you are so emotional makes it even harder for a decent man to leave you.
I don’t think you can be friends for awhile. Hanging on only makes you have hope and keeps him from having the experiences he wants and needs if he is to make an honest choice. Stop contacting him. Shut him out of your IM account. Keep conversations at work to what is necessary to get the job done. If you can, transfer to another department or get involved in a project that puts some distance between you. Let people know you are open to meeting other guys.
Yes, breaking up is really, really hard. But staying with someone who isn’t really sure he wants to be with you would end up being much harder.
I wish you well.