Presuming its true, the alternative is Trump, who is an avowed womanizer. I'm shocked that Trump hasn't come out to attack Cruz on the low number aspect of the story.
Assuming for a moment that the story is true, which I'm not saying that it is, but...
Trump's past is an open book. It doesn't seem to matter to people supporting him. Why? Because he's not presenting himself as a paragon of virtue. He's not presenting himself as "true" conservative.
OTOH, Cruz has been preaching to us from the beginning. He's presented himself as a white night, above reproach, beyond human frailties.
That is the difference between the two in this matter.
Trump was a womanizer but he didn’t pretend to be Jesus Christ either. Nor did he do it when holding elective office.