Do I have to be seperated for a year before I can file for divorce from my husband who is currently committing adultery by living with another woman?

In Massachusetts, there is no requirement that you be seperated for any length of time prior to filing for divorce.

Massachusetts has a no fault divorce, so that you can file for any reason whatsoever, or you can file under fault grounds for adultery.  If you choose to file for a fault based divorce, it is more difficult, since you must prove that the spouse cheated during the time of the marriage, with actual proof of this.