Um....

Mamahuhu, Blue Rose is spot-on. 

Questions to ponder:

*  Has he made any attempts to stand accountable for his past history with you?

*  Has he made financial restitution to you, voluntarily?

*  After 25 years, is it possible that he has run through his former source targets and is counting on your good nature and kindness to override the facts of your divorce?

Without sounding harsh, I would strongly caution you.  FOUR times he's shown up at your place of employment?!  REALLY? 

He has an agenda, Mamahuhu.  Oh, you bet he does.  He's probably run out of finances, is homeless, is alone, and needs something from you.  Beware of the "lovebombing."  This is a deliberate choice of actions that cause source targets to feel that they are "The Only One" that understands the N/Spath, or can "save" them, or can "help" them.  Beware, beware, for everything that is sacred in your life - BEWARE!

Please, visit the following site for more information on sociopaths, their tactics, and recovery:  www.lovefraud.com

This man has a terrible agenda, and it may be that you are so blindsided by this sudden reappearance of someone that you had no closure with that you are super-vulnerable.  Please, consider "No Contact" and learn more about what you are most likely dealing with.

Best wishes to you