Infidelity is one of the most devastating problems that can arise in a relationship.
Nothing causes a lack of trust and safety in a relationship like infidelity, which will rock the very foundation of your marriage.
Infidelity is commonly defined as sexual behavior performed by one partner outside of the relationship.
Infidelity can also extend beyond the realm of physical intimacy to include an intense emotional connection or attraction to someone else (an emotional affair).
Infidelity appears differently between couples and sometimes even between partners in a relationship.
What may be acceptable behavior to one couple would be inexcusable to another.
What is satisfying to one partner may be abhorrent to the other.
It is important to not dismiss your partner's feelings just because you may feel another way.
It is not uncommon to feel like your world has been turned upside down upon learning that your partner has had an affair.
Infidelity throws your normal emotional state into turmoil; your feelings can easily fluctuate from one minute to the next, and from one day to the next.
Common reactions when an affair is discovered include:

• Feeling vulnerable and unsafe in your relationship
• Believing the worst about your partner's intentions
• Questioning the future
• Believing there are other betrayals that you don't know about
• Feeling out of control in your relationship; you no longer trust that you know what your partner is thinking or doing
• Questioning your beliefs about who your partner is and about the relationship in general
• Shock, rage, depression, anxiety, hopeless, sadness, numbness, guilt, or shame
• Feeling foolish for not having "seen the signs"
• Feeling uncertain about your worthiness and attractiveness
• Feeling overwhelmed by visions of what you imagine the affair to have been
• Experiencing flashbacks of details that you have been told about the affair
• Fluctuating between wanting to end the relationship and wanting everything to be the way it was before the revelation
• Being distracted and forgetful
• Withdrawing from contact with friends and family
• Retreating emotionally from others
• Repeatedly asking for an explanation about how it happened
• Seeking revenge by verbally attacking the partner, breaking things, and resorting to physical violence which is uncharacteristic of who you "normally" are

Despite the pain and difficulty of dealing with infidelity, divorce isn't always inevitable.
With the firm commitment on the part of both partners to understand why this breach of trust happened, and the mutual goal to rebuild that trust, some relationships can emerge even stronger.
To help heal infidelity, the partner who strayed must take responsibility for his or her actions and end the affair.
He or she must also be open to answering questions about the affair to satisfy the needs of the one who was betrayed.
Take care to answer questions in measured amounts so that neither person gets overwhelmed or feels compelled to act out in ways that are further destructive to the relationship.
It is also important to clarify why the affair happened.
It is easy to blame the partner who strayed for a problem, but if you can take a step back and look at the dynamic between each of you, you might come to understand why this choice was made.
Notice what was happening (or better yet, not happening) in your relationship to lead your partner to look outside for comfort or connection.
While coming to this understanding is typically a slow, painful process, it can also foster a real understanding and bond between the two of you.