You care that you're a couple. Looking to the fantasy addiction in an attempt to fulfill our loneliness is not just a pursuit for the single person, but also becomes an alternative to avoid facing problems with your partner. This is the other face of addiction-escaping from relational problems. For example, it's easier to go to the Internet for a virtual affair, or take up with another person, instead of the real, live version. Often people turn to affairs either to get away from, or shake up a relationship that's in trouble.
Intimacy is another fear.
The Internet is an easily available addictive tool and you can convince yourself it's harmless. It's only words on a screen. Just like an affair, it takes energy away from dealing with your relationship. It's an avoidance tactic. An affair often ends a relationship, although sometimes it forces honest dialogue, if it's not too late.