>You might not want to blurt that out all to blatantly though, but implying you're turned on by someone for whatever reason is perfectly ok.

Very true and very useful.

>In the end, both men and women knows that romantic relationships is only a mean to the end, which is sexual relations.

Not auto-true.
A lot of people look for a partner in life that they also can shag, rather than someone to shag whom they also can share their life with.

>we typically spend all our time thinking about fucking.

Not true, however in a way that's unrelated to gender. Some people do that indeed, but there are plenty of people who think very little about it.