Several weeks ago one of our fellow posters, PhoenixStudies posted numerous scans showing various interactions between Jean and Bishop. They have history together as they both were members of the original X-Men Gold Team. Granted that isn't much, but at least they do have history.
I can definitely see Jean having commonality with Bishop when he was portrayed by Claremont in Xtreme X-Men. I could see her being attracted to him. I think Bishop is a great character , and I've already said my peace about how his character was assassinated in more recent years.
I also do not think Jean would have one night stands.. or if she did it wouldn't be very often. Things happen. I think it was clear in Age of X-man that Jean and Bishop remembered having a romantic history together.