I dated other men throughout the process and even continued dating one of them after my ex came back. But I just did it because it was fun.
If you're doing it for an ego boost and to feel wanted, that might come back, and bite you in the butt. When we rely on others to feel good and attractive, it only lasts as long as the relationship. You gotta learn to feel all that on your own or else you'll just be at the mercy of the person you're with.