Many contracts will try to place teachers with their partner/friend/spouse to alleviate culture shock and ease the teachers transition to the foreign environment.
If you and your partner are not married, you will need to keep cultural norms in mind. In some countries it is illegal for a man and woman who are not related or married to live together. However, as long as you are discreet about your situation, most landlords will not make it an issue.
If you are gay or lesbian, you should be aware of laws in the country to which you are traveling. In some countries homosexuality is still illegal.
If you are traveling as a same sex married couple, your marriage will be recognized in countries like Belgium, South Africa, Spain, the Netherlands, Canada, and some US states; however, in many countries your relationship will not be recognized. Please carefully research the country in which you plan to travel.