Having to deal with an extramarital affair can be a life-changing
event, regardless of whether you stay married or not. Inescapable
feelings can come over both people that will never be forgotten 
by either of them. The person who actually had the extramarital 
affair can have feelings of guilt, loneliness, confusion and 
misdirection along with many other feelings. The 'partner' who 
did not have the extramarital affair can have these feelings as 
well, but the lack of confidence that can come as a result of 
the other person having an extramarital affair can be one of 
the toughest parts to deal with.
 
The feelings that come as a result of one or both parties having 
an extramarital affair are natural but can also be extensions of 
something much deeper. Of course, if someone has an extramarital 
affair, both people in that marriage will have feelings that will 
be "surface level" only at first. Arguments can occur, denial may
set in, and/or tempers can flare due to the extramarital affair. 
While these things are only natural and to be expected, if your 
going to actually survive an extramarital affair, you must look 
at the deeper issues and get down to the real cause of the 
affair and what to do about it.
 
People in marriages don't often look at having extramarital 
affairs lightly, and they realize most times what affects 
their actions will have on their marriage. If someone has an 
extramarital affair and doesn't think that it will have an 
affect on their marriage, surely they are either in denial or 
their definition of marriage leans strongly towards the "open" 
side.
 

For the rest of the married crowd who don't subscribe to an 
"open" marriage and who have to deal with an extramarital 
affair, things can get a bit more complex.
 
Complexity can be interesting no doubt, but it can also add 
to the confusion of someone having an extramarital affair, 
especially if the couple or one party in that couple wants to 
look deeper at the situation and figure out two very important 
things:
 
  1. Why did the extramarital affair happen?
 
  2. Does the fact that there was an extramarital affair in 
     the marriage really warrant getting a divorce when both  
     people agree upon the reason that the extramarital affair  
     happened in the first place?
 

If the couple really wants to save their marriage in spite of 
the extramarital affair, then finding out why the extramarital 
affair happened and agreeing on that reason is the first step 
in the healing process.
 
If you are currently trying to save your marriage and one of 
you had an extramarital affair, try to limit your pain that you 
feel and talk things out with your spouse so you can clearly 
define and agree upon exactly why the extramarital affair took 
place. If you cannot do this, chances are you will never get 
over the extramarital affair and your marriage most likely 
won't survive...or at least you won't have a healthy marriage 
after the extramarital affair.
 

After you have defined and agreed upon the reason that the 
extramarital affair took place, you must decide whether that 
reasons (or reasons) warrant actually going through a painful 
divorce. At this point you have 2 choices...either decide in 
your own or decide with your spouse.
 
The latter is optimal for a variety of reasons but the main 
reason is that you may actually save your marriage if you 
decide together. Deciding together whether the real reason an 
extramarital affair took place indicates that you're both really 
reaching out for something, something you most likely didn't 
have prior to the extramarital affair...togetherness.
 

So, should you get a divorce just because one of you had an 
extramarital affair? No, not necessarily. Depending on how 
collaborative you can be with your spouse, how 'detective-like' 
you can act, and how much soul searching you can do, you may 
just become stronger together because of an extramarital affair. 
It may sound odd, but that's the truth. Of course, it is entirely 
possible (and probable) that if you both don't define and agree 
on why the extramarital affair took place and work to address 
that reason or reasons, your marriage won't ever be healthy again
and you'll never be able to healthily survive the extramarital 
affair.