Relationship advice!!!

I was dating this person and I was head over heels for them. But we broke up about 8 months ago. Recently they have been coming to see me at work, spending time with me, and being there when I need someone. It feels like nothing has changed. They want to get back with me and I want to too. But I am scared. However I am not sexually attracted to this persons.  Also i have a coworker that is amazing, and we hang out all the time, like two peas in a pod. And I am sexual attracted to them. I don't know witch to pick. Help!!