Why do Pisces men make things so difficult?

I have got to know a Pisces man who wanted to be friends on the internet. We know each other for 2 months now and he can be painful, selfish and mean when he wants to. He can also be so caring at times that you tend to forget his other side but that side keeps coming back later on. I think you are in a very dangerous zone when coming close to a Pisces intimately because you never know how he is going to react and take the whole thing. He is moody, complain about things which do not really need to be complained about, he can make you wait if he wants to which is literally punishment to me and I have done nothing wrong except that things did not go his way so he finds ways to punish me back. Can you really trust them? Are they good lovers? If we had a bad start usually I pay attention to signs and I think they (signs) have already warned me that this relationship can be stormy!!!