Each and all of us have some kind of weakness, a particular place where we find ourselves compromising ourselves, in spite of all the pain that comes with participating in such self-destructive behavior. The key is what does one do with this state of self, given one's proclivity to submit to the will of something seemingly just waiting to compromise one's best interests.

First, you need to see that this cycle of loathing yourself has become part of the pleasure of satisfying yourself through your acts of infidelity. The false self could care less WHAT it feels; all that matters, in increasingly obvious ways, is that it feel what it does in ever-increasing measures. This cycle is an addiction... not to the sex act itself, but to the sense of self that's generated as one repeats the self-ruinous act (whatever its nature).

You ask what to do? You know what needs to be done. If you were periodically enticed to pick a beautiful-looking staff that turned into a venomous snake an hour later, delivering a bite that sickened and weakened you for a month, how many times could you be fooled, regardless of how the "staff" of that desire was able to disguise itself? A few hours of pleasure for months of pain, or worse?

At some point you have to leave the longing for that staff on the ground where you find it, and walk away; just leave it there (with yourself, with all of its cunning lies of how this time "it's different"). There is no other answer. Seeing yourself, remembering yourself... even as parts of you "talk" to you with their soothing, appealing tones of how important, vital is this pleasure to come... and then realizing this part of you LOVES pleasure/PAIN -- because what it wants always comes in this pair.

You will have to have a new kind of (conscious) suffering if you want to stop hurting yourself and everyone else around you. But this suffering born of seeing yourself leads to the end of that level of self that induces endless, useless suffering. Everything depends on how weary you really are of lusting, justifying, and then feeling the after-lashes of the very nature that tempted you into compromising yourself.

Persist. Ask the Divine, as best you know how... NOT to save you from yourself, but to let you see yourself as you are. This prayer, when sincere, is always answered. Then you will have a chance...