A couple years ago I had a guy working for me who had a tough time dealing with a split (ironically, his wife was also a competitive bodybuilder and also worked as a trainer at a 24 Hour Fitness shop). He basically abandoned the workplace and chased after her several states away. Unemployment was low then and it's usually tough to find people in my business so I tried my best to keep him on the job, but after 6 months I had to cut him loose. Far as I know he and his wife are still going back and forth and he has lost at least one other good job over it. But at least it hasn't come to violence.
Some people can go berserk of over a break up or infidelity. They get really enraged that they can kill. Some people go really far for love.