Quintessentially,
your mindset is the source of your torment and dire circumstances.
Your rationale of what's love is to you appears to be myopic in
judgement and narcissistic in thoughts - revolving solely on how
you adorn your deluded definition of love in such screwed
pattern.
Chances are, your wife is merely a woman that happens,
unfortunately, to be around at the wrong time, with you accepting
her while arming with a 'No-fish-pawn-also-good' perception of
things.
All along, there has always been an innate dissatisfaction with
your relationship as you perpetually long for a woman whom you
could be crazy over, thinking that this is true love for you.
I am going to share with you something:
'...Many people look so
disillusioned when I announce that the soul mate search is a myth,
like I'm taking their favourite fairy tale away. I'm not, believe
me. Giving up the idea that there is a soul mate for us somewhere
and it's our job to find them can be downright liberating. Few
things bring tears to my eyes more quickly than clients who stay in
abusive relationships because they have confused the constant
emotional intensity with their concept of what having a soul mate
must be like. Even clients with perfectly
nice marriages sadly tell me that their greatest failure was in
never having found their soul mate. The term soul
mate gets mistaken for everything from infatuation to lust to an
excuse for stalking, obsession, and domestic
violence...'
I feel for your wife, not because her husband is getting
emotionally entangled with another girl, but because all these
years, she has failed in trying to induce your heart to love her
naturally.
You love the security that accompanied with her presence, but you
never did give her or yourself a chance to love genuinely. And
there's too much fantasy-indulgence that you have fed your
befuddled soul with, giving rise to all sort of illusionary
expectation you desire in your relationship.
Your loyalty is wavering - citing that she is nothing but normal
and normal isn't what you are looking for.
Have you both communicated about this matter? Seriously, it isn't
too huge of a hole to mend if both parties are willing to work
things through. Of course, if that's not part of your decision to
smooth out the edges in your relationship, then it will degenerate
rapidly.
Before you keep looking out of your relationship for answers and
hastily decide that that's true love for you, why not you try to
understand and love the woman you are with? It's kinda sad getting
married to a woman you hardly even knew or love. Sure, you might
have dated for years, but to me, the relationship is hardly
anywhere concrete.
Have you even given your marriage a good try? Or do you simply
disregard it completely?
The answer would decide your route to take. 
Cheers