What does this dream mean?

I don't think that you have any subconscious feelings for Oliver, maybe it's just because you have been spending a bit more time together and maybe you feel that that is time you should be spending with your boyfriend, and so you feel like Oliver is the only one to spend that time with. On the other hand, you might be feeling adventurous and curious about different people and maybe your relationship needs a new jump-start or spicing up, i suggest that you get more interest into the one you truly love and try and to see him more. : )