Actually, Cruz did not. 
The attack ads you speak of were created by an anti-trump PAC not associated with, not taking directions from, and not supported by the Cruz campaign. 
Mr Cruz had nothing to apologize for. Mr Trump is still a bully, and worse, a progressive. 
We needed a constitutionalist like Mr Cruz this election. In stead we allowed a statist to be selected for us. We needed someone who could take power away from the federal government and return it to the states, or people respectively. We got someone who wants to expand the size and power of the government.