Warrants typically do have expiration dates on them but what happens is that when that date gets close the court simply renews them. They can do this pretty much indefinitely. I've never seen a bench warrant actually expire.
Bench warrants are very common and each court has a process for taking care of them. You should talk to an attorney and get yourself set up to quash the warrant. If it's beent that long you might want to prepare yourself to post some amount of bail.
As indicated by others, a bench warrant does expire but they are commonly just renewed by the court so they can remain in place indefinitely. The only surefire way to get rid of a warrant like this is to appear in court. Many courts allow you to pay some money to get the warrant quashed and get a new court date. If this is not an option, an attorney could help you get on a court calendar to address the issue in front of the judge. Either way, you would need to be prepared to face the underlying prosecution on the DV charge. Even if it has been 7 years since anything happened, the prosecutor can and usually will still want to pursue the matter.
So, the question would be whether or not the fact of having an outstanding warrant is impeding your life in any significant way and whether it is worth it to you to go into court to try to finally clear the matter up after 7 years. That is a personal question only you can answer. Obviously, if you have a bench warrant you could theoretically be arrested at any time. If you are wanting to deal with this matter it would be advisable for you to speak with an experience local attorney to give you a better idea about the specifics of your individual case.