So, I have found this thread to be very fascinating considering I just recently broke up with my ENTP boyfriend of four years. There are many reasons I fell deeply in love with him--he was (and is) extremely charming, gregarious, intelligent, sarcastic, and funny as hell. I don't think I have ever laughed so hard over such inane conversations but he had that knack. We also had the most interesting exchanges when it came to science, history, philosophy, values. Perhaps what tipped me over the edge were those moments when he shared his vulnerable side with me and I peered into the pain and loss he has experienced. He also was there for me at a time when I needed someone to defend me as I can be far too accomodating for my own good.
The push/pull dynamic which has been discussed here was very much evident throughout our years together. He could be very intense in his focus and be lost for hours in studying strategy or history, and at times it did seem we lived parallel lives where he would check in with me to connect, but then he would be off again inside his thoughts, or on to the next big idea. He seemed to rebel against the "routine" of living together, and later revealed that our relationship was the most "established" (his words) he had ever been in. In past relationships he never lived with the person, or in some instances was never in love with the person but rather he preferred not to define it, just flow from person to person (he described it as a state of flotsam and jetsam, very poetic).
I think where the J/P conflict was most evident was in this issue of closure. I always feel less agitated when I know the perimeters of a problem, when I can break it down into pluses and minuses because I know my feelings can be overwhelming to me, but he preferred things not to be defined. He did tell me that I was the first person he had been with that didn't impose the standard rules and regulations on the relationship, but for some reason he did that to himself and started to resent it, even though I had never dictated how we would be together. Again, this push/pull dynamic....
I can definitely say that the ENTP/INFJ relationship can be exhilirating, but at times exhausting. Since breaking up we continue to be in contact daily and can still share some amazing insight into what went wrong and why, which has helped me tremendously understand the past which is an incredible gift I think we give each other (I am after all an INFJ so to be understood is something that allows me to put a conflict to rest).
He was very emphatic that we remain friends and said it would be a great loss if we weren't able to get over our hurt feelings about the past, so we are attempting to be just friends. I do know that I would miss the incredible conversations I have shared with him, so I can say without a doubt that the ENTP/INFJ combination has its definite advantages--a person just has to understand the dual nature of the public vs. private personae of the ENTP (and that would probably apply to all types).