Inter-office relationships that end badly often bring many hard feelings to the working environment, and these feelings tend to make other people uncomfortable when they are faced with acting as though nothing is wrong, or when they feel forced to take sides between the two former lovers. The breakup can also affect the company, as the two individuals involved in the broken relationship may still have to work together closely, participate on the same teams, and attend the same meetings. Discomfort about doing those things often doesn't occur to people when they are dating, and the problem only appears later, when they have ended their relationship for one reason or another and suddenly realize that they still must see each other every day, no matter what their feelings for one another may be. Dating in the workplace has been an issue for many years, and it will continue into the future, as long as romance and employment continue. They often do not mix well...

A lot of it depends on whether the people are compatible in the first place, just like with relationships that do not involve the workplace. There are always going to be various issues that employers will have, whether they allow fraternization or not, but it is a decision that must be made in each company. There are specific laws and regulations that must be followed as they relate to discrimination, but other than that, there are many different rules that can be decided by each individual company. The freedom belongs to the employers for the most part, and they must decide what they want to do and how they wish to punish those that cannot keep themselves from starting relationships that they are not allowed to have in their workplaces.
Bibliography

Wilson, R.J., Filosa, C., & Fennel, a. (2003). Romantic relationships at work: does privacy trump the dating police? Defense Counsel Journal.