why is that all guys think about is sex?

Question

why are they such sexual creatures? do they catch actual human feelings?

Answer 1

Because, and people tend to forget this, people are animals. And, like any animal, the male of the species is concerned, primarily, with carrying on his bloodline.

Now, does that mean that men want a lot children. No. But, that desire to have sex stems from the basic animal instinct to do so. We as humans have "higher intellgience", but those basic instincts are still in there as well.