I think that's a bit harsh Vivacia.
I speak from some experience when I say in at least some cases of infidelity the cheating has nothing at all to do with the relationship as such - it is more to do with the cheating partner and some aspect of their psyche/personality. Unless that is addressed, and it can be addressed, there is a strong danger of it happening again.
IMO the comparison with addiction is very accurate - some people are addicted to the thrill of new and secret relationships. Much like an alcoholic, the cheater doesn't cheat to hurt other people but to get the buzz that they crave - they are blind to the destruction they cause. They can and do separate the cheating from their relationship - the two things serve very different purposes for them and it is possible for them to genuinely love their partner while ag the same time having a passionate affair with someone else.
IMO cheaters like this need to hit 'rock bottom' - they need to feel in a very scary, definite way the real connection between the affair and their relationship - you can have one or the other but not both. In my personal experience, in many (but definitely not all) cases if the betrayed partner sticks around, talks, works on the relationship etc, then the relationship may limp along for another while but it will end, either because it just breaks down or because of more cheating.
If the betrayed partner throws the cheater out and they have genuine space away from each other one of two things happens - the cheater claims remorse but does nothing to mend the relationship. With a bit of space the betrayed partner gets a bit of clarity and strength, sees the cheater for what they are and realises they can go it alone. The relationship ends, definitively, without years of 'trying' (which essentially would involve the betrayed partner pushing down their totally justified feelings of hurt while the cheater plays at remorse). Or, the cheater gets a massive kick up the arse, realises just what they stand to lose, looks closely at their own behaviour, makes genuine changes to their attitude (not for their partner, for their own good) and basically learns their lesson, regardless of any opportunity to get back with their partner. The betrayed partner gets space to heal and make a clear decision on whether to move forward, without pressure to act ok. In this case, with enough foundation still standing there is a good chance the relationship will recover really well and both will move forward happy. Even if the relationship ends, both have the best outcome possible in the circumstances.
I don't advocate LTB in all cheating circumstances. But sticking around and slogging through without some crescendo - some definitive moment where separation is a real option - is a very bad idea IMO. Without some watershed moment where you're both finally being honest with yourselves and each other, the infidelity will just fester on the heap of problems that will finally topple and bury you.
Infidelity is relationship cancer. It doesn't call for tea and sympathy it calls for radical surgery, strong treatment. You need to get it all out, asap, before the relationship is beyond saving.