Like all common cases of 2-timing, yours
fall under the same catergory: of someone who seemed to be unable
to make decision for their own love affairs, but didn't realise the
roots behind this tragic scene.
Like all common cases of 2 timing: between one old lover and a new
lover.
***
Please realise by now that this mess is created due to your
conflicts between the choice you ought to do and the your
insecurity within yourself. According to CloUdiSm remix III: On the
surface it may seemed that you like two guys - but actually you are
trying to maintain this love model called LXB Model to
protect yourself and to be in the best of both
worlds.
Securities comes from your old love - you know he wouldn't leave
you, but the flame is weak. He falls under the Plain Water theory
(PWL) - tasteless but cannot live without.
The excitement comes from your new love - but you cannot gauge/see
long term future with him. He knows about your situations, knows
that you have a bf - but made mutual choice to be together. This
deceptive relationship cannot see much fulfillment.
In maintaining LXB model, people always place much empathy on their
partners - thinking that it will hurt them if you fail to upkeep
this model. But in reality, it causes more hurt.
Psychologically, at least 50% of the reason contribute to the fact
that you don't want to be label as a 'bad egg', plus the above
false empathy - you remain where you are. 
One interesting note here: You mentioned you will probably stay
with your bf because he loves you so much. Then you go about saying
how gulity you will feel when that happen to the other guy... you
spoke everything about them - nothing about you. So you are staying
in the relationship because your bf loves you alot and knowing that
he couldn't and wouldn't leave you at all? Now my question:
Are you still in
love with him or are you in love with security that he could
give?
Advice?
Like both of them? Why not see who is more suitable for you? In my
years of relationship analysis, I have learn this: No two
person are equally suitable. You can't quantity love,
therefore you can judge who you love more, but you can certainly
know in ALL aspects on a person, if he is more suitable and blends
with your emotions, lifestyle, mental frequency, and everything
else essential.
This suitability has to be JUDGE by current present
standard and NOT the past. (E.g. your bf may be suitable in the
past, but as time passed, people changed, habits formed, etc - this
may not be the case)
Drop the defensive preception of yours, thinking that they will be
hurt when you make your choice. What makes you think both of them
are damn happy now? You made a wrong move and you completely feared
regrets - but let me tell you: face them. Deception in relationship
will crumble from within. If this is a lesson for you to learn,
embrace them.
P.S: Are you a Pisces, Scorpio or Libra?
Cheers
