Anonymous wrote:I don't like the word "blame", but most of the time, both parties are responsibility for the break up.
There is no single rule - yes, sometimes one party all by themselves is entirely to "blame" and the other party is "faultless". However, this is exceedingly rare; generally both parties have to fall down on the job a good bit. It almost always takes two to tango.
Affairs are generally a symptom of a failed or failing marriage but not necessarily indicative or related to the reason for the failure. Plenty of people cheat when their spouse would gladly give them all the sex they want.