Is it possible to give someone genital herpes through oral? And then sleep with that person and give it back?

Please someone help, my boyfriend had cold sores and went down on me, and then we both got herpes at the EXACT same time...cant even figuire out who had it first. Is it possible that i transferred it back to him? or is this not possible as his body would have produced antibodies for that virus and it is simplt that one of us has got the HSV-2 and transferred it that way. Thanks xxx