Passionate and blunt, Aries are. Especially if something bothers them, they won't hold back. If they're bored in the relationship, they'll tell you.
Taureans are sensual, secretly passionate. However, s*x may suffer if they're bored. Perhaps nonexistent. They've lost passion and playfulness.
Geminis tend to waver. They switch conversations because they're bored. If they're bored in the relationship, they may find someone new to entertain them.
Cancers enjoy caring for loved ones. If they're bored in a relationship, they may stop. They don't get it. They may even look after themselves.
Leos like attention and good chemistry. They get bored without those things in a relationship. They may seek chemistry and attention elsewhere.
Critics are Virgos. If you don't impress, they'll get bored. If they're uninterested, they'll leave. They'll find something or someone else.
Libras want both their partner and themselves to be happy and loved. When they're bored in a relationship, they may stop trying.
Scorpios can be dramatic and possessive. They may be bored if they fight with you over unimportant things. Drama keeps things interesting for them.
Sagittarians want love to be exciting, adventurous, and meaningful. They may wander off if they're bored. Without their partner, they'll seek excitement elsewhere.
Capricorns open up emotionally if they care enough. If bored, they won't bother. They'll shut down again after realizing the relationship isn't working.
Aquarians like originality and a deep connection with their romantic partner. They'll see the relationship as familiar if they're bored. Just leave.
Pisceans love romantic poetry. If they don't get that in a relationship, they'll get bored and sad. They cry in their room and isolate themselves.