You seemed to have an awareness that
'something' is not quite right; somewhat skirting around the border
of promiscuity (or have your already crossed it?). Personally, that
depends heavily on your perception of what defines a 'cheating
behaviour' - apparently, you seemed cool about having light petting
and kisses with others, hence your thoughts about having 'no sex'
non-committed flirting relationship might seem to be 'alright' to
you - but I doubt your other half could readily accept this
arrangement unless this is an open relationship.
It is always good to seek additional help if you could you feel
that you are losing control. However, I just want to caution you
one important thing: it is easy to give ourselves a label of
'addiction' so as to abnegate your responsibility of your action
because we often 'attribute' the cause of our action to our
'addiction', when in fact it is but a matter of choice.
For example, have you encounter times when you need to pee, but
because of that fact that you are in the middle of a
conversation/meeting, you actually made the choice to hold your
toilet trip until the conversation ends? Surely, peeing is a
natural biological urge and it seemed crazy to stop
yourself from going to the loo - we do put ourselves in
discomforting situation unconsciously, due to variety of
reasons.
The only difference between my above analogy is that choosing to
go to the toilet abruptly is unlikely to bring about serious
repercussion from your significant other, while having sex with
someone else behind your gf's back is a
morally questionable choice. You could say that I have a 'sex
addiction' and I have 'no choice' but to keep a list of numbers so
that I could pick from the list randomly whenever I wanted, so as
to satisfy my physical needs.
However, the point is that keeping this option in this fashion
is likely to ruin your relationship in the long run. Surely you
could remain the way you are, but your outcome is clear - it is a
destructive road ahead unless significant changes could manifest.
In some cases, you might not get a second chance. If your deemed
that this relationship is important to you, then given your current
lifestyle, realistically, it does not help you to stay 'dry' and
instead, promote this 'old' behaviour in an exceeding dangerous
manner (clubbing/flirting/excessive engagement in porn, etc)
I can see that you are contemplating; however, the choice
between contemplation and commitment towards resolution on your
issue is usually separated by one huge chasm - whether we
really want to resolve it. If not, it
will end up like having eczema on your last finger - we don't
usually give a damn about it until our skin start cracking,
bleeding and flaking.
P.S: Myth buster number one: you don't have to be sick in order
to see a professional. You could see a counsellor and just have a
chat to understand about the scope of your problem. 
Cheers
Thanks guys for the responses. I am sure I am not alone on this.
It is an addiction, less of a choice, it's when self-control isn't
viable, you know? That's why I'm recongizing it and this is the
first step. I hope as well that I will be able to stop this before
it's too late.
I was actually caught cheating on her once and it utterly
destroyed her world. She has since forgave me but then again, I
know if this had happened after we were married it would have been
a different story. She also didn't know I had intercourse with that
other girl, otherwise she would have left me already.
And this is one of the two affairs I had that she found out. I
have already ended both affairs since that incident. I was actually
having 2 affairs at the same time. It was pretty crazy I must say.
Funny thing is each girl thought I was with only them. It was fun
while it lasted...
Maybe because I'm a Gemini, I think I do lead a double life. Any
Gemini out there can relate to this?
My ROM is end of this year. I hope I can improve a lot by
then.
The question I have is if I am stripped of my "choice" to
flirt/swing, what is the alternative outlet that can fulfill my
needs when my gf is not around. I must say it is the "variety" that
gives me the most excitment and pleasure and there is nothing that
even remotely come close to it (e.g. outdoor activities, friends,
gaming). I even wank to her sister's pictures sometimes. It's like
I have the complete package for me but I seek for more outside.
Like I said, it's fun while it lasted, only until I'm busted. Think
I should start looking into abovementioned consultation
helplines.