I can understand how this happened. Our instructor is all kinds of awesome. He is warm, caring, patient and genuinely cares about what is happening in the lives of his students, not to mention he is awesome at BJJ. It is not uncommon to hear about him helping someone out with a personal issue, whether just by offering them encouragement or advice, or helping them out by actually getting involved with the situation and trying to find a solution. He believes in his students and tells them so and goes out of his way to build them up.
With that alone, I can see how it would be easy for someone to form an emotional attachment to him. They might mistake his caring for romantic interest, even if there is no real flirting happening on his side of things.
But I think there is another element involved here. It is all too common for students to develop crushes on their instructors, whether it be in BJJ or in college or in basket weaving. There is a bond that forms between a student and an instructor, naturally. They share a common passion and work closely together. It is also normal to have respect and even admiration for an instructor. After all, they have a large amount of knowledge and experience in a field that the student is passionate about. And, if they are a good instructor, then it is natural to admire their character and skills as a teacher.
But sometimes a student starts to idealize their instructor. They think that their instructor is the "perfect man" or "perfect woman". I think that crushes like these are less about sex and are more about the attractiveness of the instructors confidence, his or her impressive knowledge and accomplishments and the emotional need they sometimes involuntarily meet in their students.
Wait, what was that last part, you ask?
Sometimes instructors end up unintentionally filling some emotional void that one of their students have. If a student is feeling lonely, rejected and unimportant, and an instructor tells them they are talented and intelligent, you can bet that student will latch onto that. They have an emotional void and may be tempted to try to have it filled by their instructor.
Here is the recipe for disaster in a BJJ gym:
1 student with an emotional void
1 instructor with a caring attitude
3 classes a week/6 hours a week of close physical contact and shared common interest
Why is this a disaster?
Well, for starters, many bjj instructors are married already. If that is the case, this attachment is wrong for obvious reasons. But even if the instructor is single, I would venture to say that a relationship that comes out of the instructor/student dynamic is unlikely to be long lasting. The reason why, I think, is that the bond between the teacher and the student is based more on the emotional need the instructor is filling and less on a real compatibility of two people. Healthy relationships happen when two people--who are independently healthy on their own--find common ground and attraction and build off of that.
Bottom line: If you think you are in love with your instructor, you probably aren't. You are more likely infatuated with an idealized version of your instructor and are caught up in having an emotional need met through his/her attention and praise.
What I would ask what do you really know about him/her? Do you see what he/she is like when they are not at the gym or at a function with people from the gym? Do you know how he/she treats their family? Do you know what he/she does in their spare time? What kind of music they like? What they like to eat? What books they read? What movies they prefer? What are their political views? Their religious views? How do they handle their money? Do they keep a clean house or are they a slob? How do they resolve personal conflicts? What are their dreams and ambitions?
If you've started drawing a blank about these last questions, chances are you don't really know your instructor all that well outside the gym. You know a part of who they are, not the whole.
You also might ask yourself what it is what attracts you to him/her? Do you share common ground OUTSIDE of your love for BJJ? Would you still want to be with this person if they were no longer involved in BJJ?
I am not saying that all relationships born out of an instructor/student relationship are doomed to failure. But I am saying that, if you do think you are in love with your instructor, think hard before you dive into a relationship. If it is not based on a real connection, then it will not last long. And then you will have a very awkward situation on your hands and may have to face leaving your gym and starting over somewhere else.
Also, I didn't even go into what kind of relational disasters come out of a situation where the instructor has emotional voids that they are trying to have met through their students. Can you say teachers sleeping with their underage students? Grrrrrrr!!!!!!