I would tend to disagree with DSM-3r. If you truly lied about something that was important to him and then he found out then it is your responsibility to help comfort him regarding these issues. Frankly speaking I think the testing is not a bad idea if you've struggled with this for that period of time. Yea it's not conventional and you might be a bit humiliated but in knowing that it will never keep people together, if you behaved deceitfully and have nothing else to hide then I think it's a good idea that you go thru with it. For him to offer such an opportunity to show your honesty over the last 2 years, I would almost think that you'd be anxious to show your new commitment to him and yourself.
Honesty always is best,
JB