Search Results: spending too much time together

This is a common question among others.
I have been in a so-called-relationship for almost a year with a two month break.
He seems to be a lovely individual , and we have some in common but not much.
Our mindsets are typically equal and we clash a lot but I also have Borderline Personality Disorder. Every time we meet, we can have a good, long conversation, or cuddling turns into sex automatically.

We haven't gone on too many dates. If rarely at all, we barely sleep in the same bed together, nor do we spend the night with each other that often and he has a problem spending the night with me, even though on quite a few occasions I spent the night with him. We fight a lot. Typically, when I feel offended every time he makes a plan and it changes and how he will say one thing and not follow through with his word.
He claims he's in love with me, but he keeps changing what we are. "We're friends," we're partners, "you're my fiancée" etc.

At this point I'm very confused.

I don't know what I am to him, are we actually in a relationship or are we just friends?

Have you ever accidentally fallen in love with someone or gained feelings for someone you really shouldn't have gained them for? How did it come to be? Spending too much time together? I'm kinda dealing with that, and it seems that the more I try to put it off, the more difficult it gets..