Being a lifelong Republican is not equivalent to being a lifelong conservative. The Bushes may have been lifelong Republicans, but they were liberals in the Rockefeller Republican mold. McCain's liberalism made him the darling of the media ("a maverick") up until he ran against Obama, when his media friends turned on him.
What "conservative" advocates citizenship for illegal immigrants and opposes enforcement of our immigration laws (the Bushes, McCain), supports a healthcare plan identical to Obamacare in his state (Romney), attacks the NRA (Bush Sr), raises taxes (Bush Sr again), expands Medicaid (W. Bush), joins Barney Frank in supporting the TARP taxpayer bailout of failed banks and investment firms (W. Bush), or spends billions of taxpayer dollars in aid to corrupt African countries (W. Bush yet again)?
If you're fine with all of these, you really have no basis to attack Trump. While he's far from perfect, everything he's done during his first year or so in office is far better than what we got or would have gotten from these guys.
Yet being a lifelong liberal Democrat, as Trump was until deciding to take over the GOP, is fine with you and shows no true indicator of the man’s political values. You don’t mind people who oppose the GOP. You just don’t want anyone to oppose Trump’s mercurial, ever-changing newfangled conservatism.