Thanks John for your answer. If I leave my L1 job now and the marriage and filing of documents happens, say after 1-2 months in November/December this year, is that still fine or that makes me an illegal and INS will reject our I-130, I-485, I-765 saying I was out of status for those few months. Note that I came to this country on L1 in late June of this year (on a side note, I had come to US in 2006 as well on L1 for the same employer and stayed here for 6 months).
The reason I want to leave the job is because I have found the love of my life, hence working for my current employer or another employer is not my priority, even after i_765 is approved. Right now, I want to cherish every moment of life with my fiance as we both move into marriage and begin a new life.