straight guys literally all the time are jealous about their girl being interested in other dudes but think girl-on-girl would be hot. this is so normal it's cliche. ami is just the reverse of that.imagine you are jealous about your uncle but you ship him with another boy and it'd hot.
besides, it's not like her entire personality revolves around BL now. it's just a random thing she likes and mentioned in one scene. people can have multiple interests! even multiple sexual interests! it's just a joke, not a dick, so don't take it so hard.