okay then, even if we accept that you have a part in him feeling that his sexual needs were unfulfilled (and whilst I am certainly not underestimating the effect sexual abuse has had on you nor seeking to undermine your obvious authority over what is normal for you, human beings exhibit a very wide and diverse range of normal levels of libido, sexual therapists accept ALL levels as within the normal human spectrum, including no desire whatsoever, and most people experience extended periods at some point in their lives where desire is severely limited, my point being, you yourself are not necessarily "broken", you two may be merely mismatched sexually).
so back to the first sentence, even if we pretend for a minute that we accept that you had some responsibility towards his behavior re seeking sexual fulfillment outside of the marriage, what did you do to ensure he combined it with a drugs and drinks fest, bunking off work to indulge in an aging rock-god hotel fantasy? and why high-end hookers? and why only when he traveled? what about your behavior forced him to do that?
and yes: being addicted to a substance indeed seems to create misery to the addict eventually, and I am not going to downplay anyone's personal experience. BUT lets not forget that the reason *most* people start to, and want to, take drugs and drink alcohol and have sex is because these things fire up our pleasure centres and can be enormously enjoyable, it is not to "mask their pain".
All three together, sounds to me like he was going all out to have fun.