Although you might feel like he is trying to steal your guy away, the other guy in your boyfriend's life can actually be healthy for both of you. Competing with your boyfriend's best friend for his time and attention will only result in arguments and hurt feelings. It's best if you accept that he is an important part of your partner's life and attempt to develop a good relationship with him.

Be Part of the Friendship

Make an effort to establish a solid relationship with your boyfriend's best friend. Stop regarding him as "the other man," which only creates hostile feelings on your part. Instead, focus on making him your ally. If your boyfriend's best friend appreciates and likes you, he is more likely to discourage your boyfriend from doing things that can hurt your relationship. Ask your boyfriend to plan outings where you can get to know his friend. Make it a point to include him in parties, dinners or any other important events that you plan. Always be friendly, pleasant and easygoing when you are around him.

Act Cool and Collected

It's easy to lose your temper around your boyfriend's friend if he is annoying, but it will only lead to problems in your relationship and more hostility. Be smart and keep your cool when you are interacting with him. If he's constantly pestering you, be the bigger person and remind yourself that it is not worth your time and energy to argue with him. Don't allow yourself to feel intimidated by him. It's common for "difficult people" to put attention on others to make them feel uncomfortable, says communication professor Preston Ni in his "Psychology Today" article, "8 Keys to Dealing With Problem People." He recommends regaining control in a conversation by putting the spotlight on the other person by asking questions, changing the subject or using humor.

Allow Them to Spend Time Together

Avoid making your boyfriend's best friend feel like he has to compete with you for his friend's time and attention. Allow them to spend one-on-one time together doing "guy things" such as watching football or playing video games. It's healthy for him to have someone to whom he can confide and express his feelings. Look at the positive side of their friendship; spending time away from you may make him appreciate and miss you more. Take advantage of this time away from him and hang out with your own friends. Spending time with them will help you relax and de-stress after dealing with your boyfriend's friend.

Establish Boundaries

Although you want to give your boyfriend some freedom, it's also important to establish clear boundaries so you don't end up feeling neglected and frustrated if he's spending too much time with his friend. Communicate what is acceptable when it comes to spending time with his friend. If possible, agree on specific days and times where he will have some guy time and you can plan your own activities. Talk to him if you begin to feel like he is abusing his freedom or spending too much time with his friend.