Most sith dont realy love in my opinion, its more of an obsession over their passions then realy love.
sith are drived mostly by selfish desires.
Obi wan simply loved satine for what she was and her loved him as such, its very clear in this episode when Maul tells Obi to release his anger and satine tells him not to.
I wouldnt say they werent driven by their passions they are human after all, but both of them didnt let these feelings to become obsessions and cloud their judgements. Not like Anakin for instance.
He was enraged for years, but he even tells to Obi that he planed all along to kill satine in the moment he understood what she meant for Obi wan. It wasnt Obi wan fault, not realy.
Obi Wan let the discipline cloud his judgement, that's why he failed.
No, he said he wait for years but in truth he never knew Satine before he met Viszla.