First, let me say how sorry I am that you have to go through this. Three years is quite a bit of time. Break ups are especially hard when you have to work with a person you just broke up with. If you have to work in close proximity with her, I would suggest you maintain your professionalism and be respectful so your job security is not an issue. I don’t know why you mention how she looks, the OCD or why you mentioned her insecurities. At this point, those things are irrelevant as well as unimportant. Not only are her problems irrelevant to you, saying she has OCD is wrong. OCD is a medical term. If you are not a license therapist, please don’t label or use it to define someone else.
Some how you are going to have to find a friendly medium so can work get along with her in the work place. The only way to avoid drama is not take part in it. If she says something you don’t like, ignore it. Avoid being alone with her so unpleasant altercations don’t take place. You can only control you own actions, not the actions of others. The best way to move on is to take it day by day. Always be respectful; regardless of another’s animosity or immaturity. Not only is the right thing to do, it will better for you and help you move on more easily.