I believe DB was an option for increased wealth, perhaps the ASPD JA had visions of marriage and slowly poisoning him, perhaps she found dirt on him in hopes of pressuring a marriage with blackmail, and now that same blackmail causes the man to bend over for the "girl".
Psychopath JA grew bored of the game with DB, She could not profit from that relationship - no marriage. She moved on to TA and he played her hard (in her mind). She was used to being the one in control (in her mind). This is really quite obvious when looked at from the perspective that JA has zilch in the feeling dept. unless it has to do with her.
Her life spiraled quickly out of whack due to her insatiable narcissism but also her psychopathic drive. DB, MM, BJ and TA were all a means to an end, unfortunately she is not very good with her game/lies. Many people on the outside have never been caught for the atrocities they commit because they are far more savvy than this failed criminal.
JA is dumb....she knows words (not necessarily able to pronounce them).
IMO