Welcome, studentdoc! I am also a student doc. It'll be nice to have another med student around this joint...
Re: the murmur: tons and tons of people have murmurs and they are very often benign (meaning they don't cause any problems). It's quite possible that your husband has had this murmur all his life. I'm sorry to hear that he has end-stage liver disease; that must be very difficult for him (and you). I'd echo studentdoc's statements and say it's best to address this concern with his doctor as soon as you can to eliminate any unnecessary worry. Best of luck to you.