Halacha and Bean Counting

I recently got an email regarding an old post   https://daattorah.blogspot.com/2008/09/non-jewish-prostitute-versus-jewish.html

Question is would Reb Yakov advise having Jewish girl friends with the likelihood of sexual relations even though it would result in kares rather than have non Jewish girl friends?

In other words do we approve  a secular Jew sacrificing his soul to preserve the Jewish people?