That's an issue with the ink breaking down and shifting. The technology has advanced quite a lot since your husband got his tattoo (and, odds are, the standards of the tattoo shop where he got his were a lot lower than they are today).
One of the upsides of tattoos becoming mainstream is that there is a lot more demand, and therefore supply, for quality tattoos performed in a hygenic and safe environment by well-trained and skilled professionals. I've seen some amazing tattoos that are fit to be framed as artwork.
I got mine done in a shop in Georgetown, here in DC. The cleanliness and professionalism rivaled my doctor's office.
My husband got one or maybe both of his in Baltimore when he was stationed there in the USCG. I tell him(a non drinker) that they are proof that he has been drunk at least twice in his life.