I've been through number one before - Staying quiet or distant or distracted/less interested when you're alone together, a lot of sighs; Neglecting you in front of his/her friends; hasty kisses/hugs etc; short conversations.
Generally, less interest and effort into the relationship.
Number two...well, yes I do believe in them - they've been correct for more than once for me - Capricorn is the most loyal, in my opinion - I've a close friend, who's known me for 10 years - she's never lied to me and is always honest to me when I ask her for advice and expresses her concerns etc. Otherwise...I think, cancers (definitely) and virgos...of course taureans.