I think that would be rather contrary to her character at this point in the story. She will likely feel remorse for the shower scene and confused. More “evidence” of David’s cheating, coupled with fight and/or alcohol would make her ripe for Chris. Something has to happen to further lower her inhibitions. True Netorare is overcoming the reluctance of the person. Whether that is through emotional manipulation, alcohol, lies, blackmail or whatever. Anna willingly participating without undue influence is simply cheating. Now each successive encounter may make her more pliable, but the continued turmoil, guilt and initial reluctance Is what makes Netorare. Just my opinion.