Dear Worried Girlfriend,
You have every reason to be worried. Drinking related accidents are the number one cause of traffic fatalities in North America. You are risking your life every time you get into a car with someone who has been drinking. Your boyfriend may think that he is being "cool" and manly by getting behind the wheel after a few drinks, but don't put your faith in his ability to react quickly enough to save your life or the life of a young child running out between parked cars. Hundreds of thousands of innocent people die every year due to impaired driving related incidents. You, your boyfriend, or any of your friends could become one of those statistics.
If you really care about your boyfriend, don't give in to his choice to drink and drive. Let him know before you go to a party that you will not get in a vehicle with him after he has been drinking. Make sure there is a designated driver there who can take you and your boyfriend home. If you can, convince him to give you the keys, and do not allow him to have them unless he remains sober. If your boyfriend is unable to accept your wish to keep him and others alive, dump him!
Annie