"I know how I am voting now, and it is not those two."
Did you vote on the referendum for proportional representation? If you did how did you vote?
If you didn't vote, or voted for BAU, these are your options.
If you're happy with your MP, vote for them, to block others replacing them.
If not vote for the first runner up party from last time. Doesn't matter who they are. They have the best shot of getting rid of your sitting tenant.
Those are your options in a first-past-the-post system. A system the UK shares with all these fine nations. fine nations. although not with any part of Europe.