Michael had another reason for leaving Tahoe that very night:

Michael knew that, although he was the target, Roth had no scruples about killing Kay or anyone who got in the way at Tahoe. So, by removing himself from Tahoe, he removed the target. More important: by sucking up to Roth, he bought precious time to protect himself and his family. His guiding principle, as he told Hagen before he left, was: think as those around you think.

Michael saw that Roth was very careful to mask his role in the Tahoe attack. Roth waited for Anthony’s party because he knew that Pentangeli would be there, contentious over Michael’s support of the Rosato Brothers. Frankie therefore had perfect motivation to kill Michael, and would have made a perfect patsy. Since the attack failed, Michael figured that Roth would have to strike again quickly, before Michael figured out that Pentangeli wasn’t the guilty party. By visiting Roth in Miami, by affirming that their deal was still good, and most important, by agreeing to go to Havana, Michael was helping Roth to find a reason to keep him alive until then, and to leave his family alone. That gave Michael time to figure out who the traitor was, and to plan Roth's demise.