You make a fair point. He was apparently living in Washington D.C. from 1999-2003. Of course he didn't marry Heidi until 2001, so you'll have to strike one or two years off of that window.
But the implication here is that he was using the Madam's services while he was a Senator, and that's just straight up wrong, and an attempt to deliberately mislead people.
No the implication is not that he was using DC Madams services while he was a senator.
However, there is a separate story of using hookers as a US Senator, but it has nothing to do with the DC Madam.
2 Totally different time frames, and supposedly 2 totally different sets of hookers. Not even the same people were hired. The National Enquirer appears to be pursing a story about more recent supposed interactions between Cruz and hookers but the DC Madam who had already died many years earlier was obviously not linked to that current lollipop person.