I feel that there are different types of infidelity,
A, Its just the person and they can not change their ways and do not really want to.
B, It happens just the once due to various circumstances
C, You can not help yourself and wish you could be different
I have met all three kinds of cheaters, as for can you forgive again it, depends on what kind of a person YOU are, my friend was with her husband 26 yrs and he cheated on her, she tried to patch things up, carry on but she just could not, she still loves him very much and is a mess without him, even now 6 years later but she just can not take him back.
To think that London, or anywhere else for that matter, does not belong to any one demographic