I think clearing himself from some suspicion was a good idea--that way the folks doing the investigating could focus on what really happened to her. He didn't do anything wrong other than have a dingbat for a fiancee.
As for your insight into his character - I think there is not a great deal of information on which to make that projection. There's a lot more information on which to make the assumption that she may be mentally ill, in which case he dodged a bullet.
And, BTW, the prevalence of mental illnesses in women is one of those things that are not politically correct for discussion - as a consequence you see commentators like the "expert" from Seattle on CNN this morning - explaining away this woman's actions.
Anyone has a right to change their mind in anticipation of a wedding - they do not have the privilege of wasting a lot of law enforcement resources on a wild goose chase.