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.