Lying

I misread the question. I missed the part that said "which is worse" and thought you were asking which you should do, so I voted for "I will not end my friendship".

If your boyfriend truly loved and trusted you he would not demand that you drop a friendship you've had for 14 years and would not make you choose between him and a friend. What he's doing is controlling and manipulative, all driven by his own paranoid insecurities. You should not lie and not maintain a friendship behind his back because there's absolutely nothing wrong with being friends with someone of the opposite sex. Tell your boyfriend very clearly that you are not going to end a friendship with a friend you've had for so long, and that's final. He can either learn to live with it, or he will end the relationship (in which case you're much better without him).

I agree with skyfox.If he really loved you which involves trusting you he would not ask this .If he cant accept this then he isn't worth trying to hold on to .Kick him into touch.