What do you follow?

You've heard all the cliched suggestions ... follow your heart, listen to your gut, follow your instincts ...
Listen to you heart, there's nothing else you can do;
I don't know where you're going and I don't know why;
Listen to your heart, before you tell him goodbye ...
These cliches are overused for a reason -- they are true.
A friend recently told me she's taking a break from her serious relationship. She thinks she's making a mistake by putting the brakes on but is unsure of what to do:
On the one hand she loves him but on the other hand her heart is telling her otherwise. A part of her -- a tiny voice in the back of her mind -- is telling her that she needs to see what else is out there. This tiny voice is the archenemy of the rest of her feelings -- the feelings of love and mostly-contentment with her boyfriend.
She asked me why life has to be so hard. I told her that life is hard. If anyone tells you otherwise, they're selling something -- a pill or lifestyle or even an outfit or meal. Something that will make you happy and do wonderful things for you.
You can seek happiness but will never be satisfied and truly happy. Happiness comes from within (another popular cliche).
When times get difficult (you look at your partner and aren't completely satisfied) we look somewhere else for satisfaction. If there is a problem then the relationship must be wrong. It can't possibly mean nothing is perfect and there are going to be highs and lows -- it means this is wrong. We want satisfaction, living in an egocentric culture and time. We want quick fixes. We're busy and don't want to wait.
Of course it's not that simple. Relationships are complicated, as is life.
She feels cold feet. She has feelings needing to be explored. Loneliness, feeling crowded and unsure.
So where is the balance? What's the answer Trebek?
On one hand: relationships are never perfect, especially if you receive most happiness from outside sources. You are going to feel negative emotions from time-to-time, if you're married to Joe Smith or George Clooney. Yeah, you're best friends and love each other deeply but everyone needs space. Alone time or time away from each other. Absence truly makes the heart grow fonder.
On the other hand: there's the damn voice. The tiny voice. It won't shut up. This early in the relationship, there's a good chance it's going to get louder if you don't entertain it, wine and dine the tiny voice, take it out for a spin. Or it could turn up mid-life or the mid-life voice is something completely different.
So what to do? This is life. Decisions like these are the ingredients for life. It's like those damn "Choose Your Own Adventure" books. So whats it going to be then, eh? You can't just finish the book and go back to the beginning and choose another route. The time is now!