I agree, if you voted for your representative solely on the stand he made on a particular issue, you wouldn’t want him to be persuaded otherwise.
As you live in a representative democracy, you might be better advised to spend more time thinking about the candidates on offer and choose someone who has plenty of real life experience, common sense and discernment, who would be able to pick their way through the moral, economic and ethical maze with some authority. If you select someone purely on their “stands” you are always going to be disappointed, as the only person who completely agrees with you on everything is the handsome fella you see in the mirror in the morning :)
That’s the funny thing about having a consistent political philosophy. I don’t have to worry about what a given person who shares my philosophy is going to do. It’s not random like it is for most moderates.