How long should I wait to have sex after a breast augmentation?

After the first week following surgery, you can have sex as soon as you feel comfortable enough to do so. That being said, sexual activity should not involve your breasts for 6 weeks from the time of surgery. While this may sound conservative, a capsule is forming around the breast implant and bleeding can occur if the the capsule is unintentionally ruptured during it's development. Such a rupture can be due to aggressive manipulation of the breast and can occur within the first few to several weeks after surgery. Even small tears that lead to small bleeds can theoretically lead to capsular contractures. 

In theory you can engage in sexual activity the day after surgery. Specially if the implant is not placed under the muscle (e.g subfascial) in which case you will have very minimal pain. However, it is important to:
not have your blood pressure increased, which can cause bleeding and short or long term complications for the implant,not have the implant displaced due to aggressive squeezing.Therefore, I usually permit sexual activity a week after surgery with care and totally normal activity 6 weeks post surgery.Hope this helps,Ali Rıza Öreroğlu, MD FEBOPRASEuropean and Turkish Board Certified Aesthetic, Plastic and Reconstructive SurgeonIstanbul, Turkey

Most surgeons will tell you to wait at least 2 weeks. The reason is that we don't want your blood pressure rising too much as that can lead to a blood collection around the implant called a hematoma. You should also avoid all other activities that raise your blood pressure, like working out or getting overly excited.  After 2 weeks, you should approach it carefully.
Avoid movements that can cause you or your partner to dislodge the placement of the implant for about 6 weeks. You should also follow the advice of your plastic surgeon. Hope this helps.