Abe left Morning Musume in January 2004 after she joined the group as its first generation members in 1997 and became a solo singer and actress after that. With her impending marriage, all 5 members from the first generation of MM are attached. As for Yamazaki, he is a regular in many musicals and stage plays and was recently seen in the TBS Autumn 2015 drama "Shitamachi Rocket".
Coincidentally, Yamamoto Koji and Horikita Maki who got married this year also acted in the same play during May 2015 although Yamamoto played the lover of the married heroine, not the husband.
Source: Oricon / Nikkansports