Welcome to the forum. I'll try to help.
I'm sorry to hear you and your husband have been worrying about this, and modifying your sexual expression with one another. You're going way overboard in trying to prevent transmission to one another. You don't even need the Famvir.
Once someone is infected with HSV of either type (HSV-1 or HSV-2), s/he develops immunity to a new infection with the same type and is very unlikely to ever catch a new infection on a new part of the body. Therefore, couples never "ping-pong" their HSV infections back and forth. In fact, one of the standard counseling messages we give couples with herpes is that there is a silver lining in both members having the same virus strain: that they need never worry again about transmission to each other. Neither your nor your husband is likely to ever catch your partner's genital infection orally. And for the same reason, auto-inoculation -- i.e. spread of the virus to a new spot on your own body -- is also very rare. Finally, in your situation, the near-zero risk of transmission is even lower since you're taking Famvir.
My advice is for you to speak with your health care provider(s) about this, and discuss whther to stop taking the Famvir. The main reason for suppressive treatment of genital herpes is to prevent transmission to people who are not yet infected; or to preven frequent outbreaks. If either of you starts having frequent outbreaks after the drug is stopped, he or she can restart it. But it definitely isn't needed to prevent transmission to each other. And by the way, herpes never spreads to internal organs, whether by oral sex or any other way.
I hope this gets you started on a path toward more rewarding sex in your marriage. Really, you should not be at all worried about herpes. There is no risk to either of you.
Regards-- HHH, MD
Thank you so much for your prompt and thorough answer. This is very helpful information which I am going to be happy to share with my husband! Bless you!