As someone who is not a fan of mushrooms, you most definitely can taste them in anything they are cooked in (the same is true of many foods, particularly those that contain oils or complex structures that leave remnants when cooked). That's why things like truffle butter have a distinctive fungus taste despite not having chunks of fungus in the butter.

Perhaps this is judgemental, but I definitely read your comment as if you said it with some snark. Give your boyfriend a break. Grown adults are allowed to like and dislike things differently from other grown adults. Those likes and dislikes can be deeply rooted in unpleasant things, sometimes.