Sounds absolutely disgusting! There aren't many things that I intensely dislike, but Marmite and peanut butter have been lifelong no-nos for me. I remember being at a friend's house one summer when I was about 11 - several friends having a picnic on the lawn under the apple trees. A check tablecloth was spread out and plates of dainty crustless sandwiches were brought out, with buttered scones and jugs of homemade lemonade. Sounds idyllic, doesn't it?
Until I bit into a cucumber sandwich and found it included Marmite . I was too well brought up to make a fuss so I managed to swallow that mouthful somehow and, when no-one was looking, I slipped the remainder of the sandwich into my pocket for later disposal