Pisces (not all) tend to have addictive personalities, but this can be in any form — a person, substance, etc. It’s not limited. Pisces deal with a lot internally, more than most people can imagine. Because of this, their form of addiction is that stress reliever.
Taurus values security in all forms. Once trust is questionable in their eyes, that security net is broken and gaining it back is not easy because of that fear you’ll do it again. This makes it hard for them to proceed in relationships as well.