Good. I will not vote for anyone who endorses someone other than Trump, and that includes our soon-to-be-former Senator Portman. Any Republican who doesn't want to be damaged goods can endorse Trump, or they're part of the problem.
If your guy winning the nomination isn't enough for you, and you plan on extracting vengeance against any Republican who supported someone else in the primary, then I'd say you're part of the problem.
I'm not sure what it is with some of you Trump supporters, but he's not being elected dictator for life, or even dictator for six months. He will be able to accomplish almost nothing of substance as President unless he can get Congress to go along with him, and putting Democrats in control just to spite Republicans you don't like is basically political suicide.
Honestly, it is a worry that attitudes like yours that make me less than 100% sure I'll support Trump as the nominee. If he wins the nomination, and then goes to war against the rest of the party, I won't vote for him. Rather lose the Presidency then put someone in office whose mission it will be to turn Congress over to the Democrats.