I don't think you're the only one, but as it so happens, I went the other way, I shagged Olivia because you ended up shagging Elena without rubber later on anyway, so it was better to get the dick wet on both XD
But then again, I did make a new playthrough and play D-route only, haha, mostly because I'm a monogamous type, but also because Elena is not my type at all, I don't even like her because of her personality, plus I'm not into lolis, and Elena and Jennifer are both lolis, so no harem for me, and Elena most definitely not getting it down with D, I rejected Elena every time possible and so did D, Elena gets the boot for as far as I'm concerned, if I want a harem, there are better babes for that, like Georgina, Olivia, Cassandra and so on, well, that's assuming they'll be available (again) later on in the story