It goes against the PT Obi, who was resolutely chaste, but not the OT one, who is suggested to be something more like the maverick we got in Qui-Gon. I personally wouldn't mind this. It would humanize him a little (Satine did, which was why she was a great addition to the overall story).
In what way is Obi-Wan a maverick? He seems to be living a very modest, quiet life, watching over Luke from afar just as he set out to do since the twins' birth. I always took it that he was serving some kind of self-appointed penance for Anakin's fall, living in isolation all those years on Tatooine. To suggest that he found time for a relationship at some point would mean he abandoned that post for a considerable amount of time - unless he found someone to live with him in his little hovel I suppose. I certainly can't see Obi as the type to have a one night stand. Just feels very out of character to me.
As for Satine, I thought that plot point as intended to demonstrate Ob-Wan's restraint and determination to put the Jedi order ahead of his personal wants and feelings in contrast to Anakin's more self-serving behavior. If he had a relationship with Satine and knows what Anakin is going through with Padme, but never discusses it with Anakin, then he's probably one of the worst mentors of all time. That again seems out of character for Obi-Wan to hold back an experience that could help guide Anakin.