You are entitled to your opinion, but don’t tout it as being a fact.
Can you think of even one significant issue where they disagree? Do you think it is just a coincidence that Donald Trump was a heavy financial backer of Mitt Romney in 2012? And fairly early on?
Yes, they are having a falling out now, but that is over style. Trump feels, and probably rightly so, that Romney blew a very winnable election with his Casper Milquetoast approach.