Post deleted by I'M GERMAN-IRISH

Roth attempted to assassinate Michael because Michael was muscling in on--taking over--Roth's legitimate Nevada gambling empire, and he had designs on Roth's Havana casinos as well. Roth concluded (correctly IMO) that there was no room for both of them in the legitimate gambling world, and he resolved to get rid of Michael before Michael got rid of him.
Roth no doubt was pissed at Michael for whacking Moe Green, but I doubt that it had anything to do with Roth's move against Michael. Roth cited Michael's elimination of Moe Green in that famous Havana scene as way to divert Michael's attention (and indignation) from the Rosatos attempt on Frank Pentangeli.
The Rosatos had a beef with Pentangeli over three territories in the Bronx that Clemenza had allegedly promised them. Roth allied himself with the Rosatos against Pentangeli as a way of driving a wedge between Michael and Pentangeli. Frankie was Michael's man in New York. Roth had two objectives in mind when he supported the Rosatos against Frankie: 1) to make it seem that Frankie, not Roth, was behind the (attempted) assassination of Michael in Tahoe; and 2) to set up the Rosatos to take over the Corleone operations in New York after Michael was dead.

We never learn what happened to the Rosatos after the cop busted up their attempted assassination of Pentangeli. In the penultimate boathouse scene, Tom says that "Roth and the Rosatos are on the run..." Michael replies that he doesn't want to wipe out everybody, "...just my enemies..." Since Tom mentioned Roth and the Rosatos in the same breath, and since Michael had Roth killed at the Miami airport, we might infer that the Rosatos were included in his "enemies list." But we never see it happen.

One question I have about Frank was - why did he kill himself? Was it in trade to give protection for his family?