I don't usually reply to threads as 99% of that in existence [in
sgForums.com] are really
".........................................................".
Kudos to you for having taken a very mature and objective viewpoint
of the situation. I understand that you find yourself in a rather
precarious predicament; not being a direct party, yet holding
enough influence to stack certain odds. I am also glad that you
have (at least, as evident from your post) extended unconditional
support for and towards your sister.
As far as my humble opinion goes, I think that ultimately it is for
you to balance and weigh each guy against the other. Whether one
finds superiority over the other (in your view), would be
influenced by what values you (as the third party performing this
balancing act) hold in higher regard, and equally, what negative
traits you detest more - for example:
Weighing the positive:
BIL - long term relationship
New Guy - fresh start
Weighing the negative:
BIL - deceptive
New Guy - seemingly without morals or values (i.e. chasing before
wedding)
Of course you would find that such positive/negative values tend to
veto each other; above all, you should be guided by your own raw
instinct, whilst taking into the account the feelings of your
sister.
I would also add that long term relationships that have been broken
by deception usually remain irrepairable - sometimes a fresh start
is the only alternative; equally, something new may prove just as,
or even worse than the preceding deception. It is for you to decide
which holds greater truth.
Personally, based on my
own values and beliefs, I think your sister should stay with
your BIL; she could prevent any future incidences by being more
careful - it will be good reason for her to monitor their finances.
I must admit that I feel that your sister, BIL and the new guy have
more or less resigned to a number of conclusions:
1) Your sister has more feelings (emotionally) for the new
guy
2) Your BIL recognises this; so does the new guy
However, because of this new guy's sudden foray and very probably
destructive entry, it sounds all too fishy for me to think him as a
man of integrity and good standing worthy of your sister. Your
sister probably has a little girly crush on him, and that can very
possibly be attributed to the fact she is bored with your BIL - the
so called "X* year itch" (*X = numerical value, some people say 2,
some people say 7).
Hence, my conclusion. I do not think your BIL is that great (in
fact, I think he is no bloody good); rather, I think that the NG is
absolute trouble - to the extent that your BIL is much better in
comparison.
Good luck!