But Ted Cruz campaigned with Trump, so that says enough for the "real conservatives", Ted must not be one.
You seem to think it is significant that Cruz maintained a good relationship with Trump, and even campaigned with him, early in the primaries.
Cruz worked to maintain positive relationships with everyone throughout the primaries, focusing on his own principles rather than on the competitors themselves. That is how a serious candidate maintains party unity. Trump destroyed unity by making it personal when Cruz's poll numbers got ahead in Iowa, he made it more personal when Cruz won Iowa, and he insulted Cruz's family when Cruz continued to compete. Unity is now completely destroyed, because of Trump's megalomania, not because of Cruz's ambition.
Cruz's attempts to maintain a positive relationship with Trump, and with the other candidates, early in the campaign do not diminish or indict him now. They prove that he led toward party unity. Trump has made clear on multiple occasions, through words and actions, that he does not care about party unity. To the extent that others do, they should look to their chosen leader, who destroyed that unity, to take the necessary steps now to repair it. Perhaps by learning from the example Cruz set early in the campaign.