Hm... maybe it's because I have negative crew respect, but I can't reject anyone, so... I can't pursue anyone exclusively. Maybe you need to go positive respect route to attempt to pursue one person.
I did manage to accidentally reject Snake, but that's just because the option is worded very, very, very strangely. I thought I was entering a business relationship involving sexual favors, but apparently, I was actually removing all business options and making him despise me. Upon looking back on it, I... think this is amatonormativity in action. I decided I don't want a romantic relationship, because I don't, but the general populace considers sex to be romantic for some reason (it isn't).