Remember, it is likely the both indulged in Absinthe, which has hallucinogenic properties. If high, they could have fought and to me this is the most likely outcome. For those who have stated this should be wrapped up, investigations take time. This isn't a TV show; a woman is dead and I myself couldn't believe he walked away. The complete silence from her spouse and deletion of SM acct's speak volumes. There has been no plea from her SO to find her killer. This math is clear.
No need to plea to find her killer if she fell and hit her head.