So, when his finances were about to be revealed in the divorce case, he had to kill Jennifer to keep them from being exposed.
Now, when his finances were about to be revealed in her murder case (and perhaps send him to jail) he tried to kill himself.
He is willing to kill/die to protect the truth about his finances from being revealed.
From the DM "friend" comments, it seems that FD decided it would be better to die than to endure prison. Why didn't he think of this earlier? Did he really think he was going to get away with it, when he was driving down the Merritt on the 24th, when he was biking along Weed St that morning? Did NP and KS egg him on to believe he could get away with anything? They appeared to have set up an alternate bailout that morning, so clearly they were continuing in that vein.
Does it seem a bit odd to anyone else that nobody was accompanying FD driving down to court this morning? He was just going to hop in the Suburban and drive down there on his own?