Go out with girls like you already do... but LEAVE THEM in the club and find some pussy AWAY FROM THEM. This is what I have been doing, I go out and chill with girls, but leave them and keep meeting up again every so often for a dance/drinks (make them pay and say you will get next round in)

I can't explain WHY they are cock blocking you, but try not to be bitter about it, instead, just assume its cos they wana fuck you too