I'm going to lie about liking somebody in a relationship when explicitly asked
Why would you want to do that?
I'm afraid that if I told the truth he will dump me.
A relationship is based on trust, and lying quickly erodes that trust, hurting both parties in the process. By lying to your significant other, they will feel betrayed by you and that can lead to a breakdown in communication, damaging your relationship.
Whatever, it's his loss if I get caught lying.
It's your loss as well if you deceive him. It's not easy to live a fake life. You better tell him the truth and find someone else who you will truly love.