Its silly
because I doubt she truely understand the man she is getting. If
she already knew that he is 'like that' and still go ahead to marry
him, she shouldn't be complaining now since the both of them had
their fair share of understanding, knowing one another during the
relationship. And no, 3 years or even 10 years is still no excuse -
if it doesn't work/suit, no amount of time could change the course
of fate.
But then again, one thing I don't blame her is because most people
do not realise that marriage and BGR is one hell of a two different
thing. Especially when the guy is routine-run and as a girl, would
like their partner to ocassionally spice up the relationship. A
good man has strong principles, therefore, when he thinks he is
right, he wants you to understand the reasons why. 
Analysis:
Ok, external factors pops in when she felt a little unsatisfied
with the relationship. This would probably be a passing phrase, or
a complication if it is not properly handled and by the looks of
it, its heading towards the latter.
Her love is young and misled - she has a fear of betrayal (probably
from past experience or personal phobia) and is willing to accept a
man whom she know that would never betray her.
That doesn't equate to compatiability and
love.
The appearance of this japanese guy is dangerous to the
relationship, not because he wants to chase her, rather, SHE would
subconsciously compare and probably find the qualities she couldn't
find in her husband in him, and this will lead to love
complication.
In this case: platonic friendship is
impossible.
The next hell is her husband's respond to restrict her. This is
definitely leading her towards her complication. Her husband's
suspect not only possible affair outside, rather, he would know
that she has been seeking shelter and ranting about her marriage -
which by a man's ego AND kinda skeleton in the cupboard.
In all cases: elimination will only surface
problems.
Advice:
She needs to talk to her husband about it. They both have been
newly married, things that should/could satisfy each other in their
marriage life, physically, emotionally and spiritually must be
communicate, understood and learn to work towards them. (Sexually
must be fulfilling (both) - for her - her emotions dis-satisfaction
must be adjusted and corrected, in turn, her husband should
influence her to make her feel more complete spiritually)
In marriage, its all about complementing and adapting. She can't
just keep quiet, learn to talk things out.
P.S: Nothing to do with christian - non christian marriage. Even
non-christian/christian marriages faced such problems for this is a
common scenario. If God wants your marriage to have meaning, God
will drop problems occasionally because God wants you to grow and
mature. Before you can gain wisdom, you need gain experience.
Cheers
