Hi, I understand your concern regarding how your relationship is perceived but I don’t think you should let it bother you to the extent that it is. If you love each other then that is the only thing that should matter and you should let that allow you to focus on this petition.
I don’t think you are going to be judged for the type of relationship you are in by US officials during the process as there are many people in similar positions that have either been through the process or are going through the process as well. They will be reviewing the evidence you submit, your interview answers, etc.
The K1 visa process will challenge you mentally (it did for me and my fiance at times) but it will be ok. Just take one thing at a time.