https://www.snopes.com/fact-check/women-retain-dna/

Fake news.

Let me quote the bits you hv missed reading from Snopes article

1. Rating:  FALSE

2.The linked study, in fact, does not once mention sexual intercourse as a proposed mechanism

3. makes only passing reference to the possibility that sexual intercourse alone could contribute male microchirality to women, noting that the issue has yet to be studied.

4.  That paper, which was fairly limited in its dataset, makes it clear that the sexual intercourse transfer of male chimerism remains entirely speculative:

5. Far from demonstrating that 100 percent of a woman’s male sexual partners have male cells that de facto become part of their body, the studies cobbled together by YourNewsWire show that even if sexual intercourse transferred cells from a male that later became incorporated into the female partner’s body (which science has only speculated about at this point), it clearly wouldn’t happen in all cases.
6. We are also unsure, for the record, what motivation would exist for scientists to hide the truth about male microchimerism in the first place.