In my mind, this is the most likely scenario. The girl either did not get as much (snuggling, a morning phone call,etc.) or more (anal penetration, rough handling)than she bargained for.
You left out rape.
Are you contending that even if someone engages in consensual sex thinking it would be normal sex, that they can be forced to submit to anal sex?
I would have my husband charged if he did that to me (which of course he would never do).
And please note I am asking as a general contention, not saying this girl consented and then "got what was coming to her if he wanted anal sex", which I find a stunning and sick position that I've seen some here embrace.