I am currently in a relationship with my best friend of 3 years now, and we both have been together for about three months. During those three years, she has told me multiple times (or has hinted at least) that she has liked me, but multiple times I have had a talk with her and said that I just wanted to stay friends; the reason being is because I am horrible when it comes to feelings and being in a relationship. I'll like someone and she'll like me back, but as her feelings for me increase, mine will slowly decrease, and I didn't want that to happen.
This year, however, in January, I was considering the possibility of simply asking her out on a date. There were some feelings that I had for her, and I didn't want to regret not asking her out on a date before she leaves to another University in two years. So I asked her out on a date (just to try things out and see if they would work) and she said yes. We both went out and things went pretty well, aside form the fact that I was nervous as heck. We both agreed that another date could be in order, and it was.
Somewhere in the relationship, she came to the conclusion that we were now boyfriend and girlfriend. I realized this when her Valentine's Day card said "To my Boyfriend.." I didn't want to make things awkward with her, so I just went along with it, and we've been " officially bf/gf" ever since. (for the record, it was probably my fault for not saying anything soon enough, so she is kinda justified for making that assumption)
Things have been going pretty well, I must say. We both are conscious of how relationships work and are mature about it (we don't start unnecessary drama with each other, etc.), and she's independent enough where when I insist I pay for her, she'll refuse.
The "problem" that I am having is how I am currently feeling in the relationship. I don't feel 100% happy around her all of the time. I understand that that is a pretty high expectation for a relationship and I shouldn't shoot that high, but there are times when we're together and I have nothing at all to say, and I feel like the chemistry (on my part) just dies. Upon first greeting each other, sure we'll be flirty and do bf/gf stuff, but after some time during the meeting, that'll just fade away. When I'm not around her, I don't really think about her, and when I do think about her, I don't get any butterflies or anticipation to see her again.
Basically, I don't feel like I have 100% chemistry with her despite the fact that the relationship is going very smoothly. It would be rather awkward to just randomly call things off because of some uncertainty on my part, but I'm not completely fulfilled/satisfied in this relationship, and if this relationship ends up becoming a marriage, I'm not sure i'd want to feel this way in the marriage. I'd want to feel 100% confident that she's the one for me and that I'm willing to do anything for her out of love instead of out of expectations from the relationship rule book.
What should I do? Any thoughts on this?