Confused and worried for my cis girlfriend

This will be a long, somewhat stream-of-consciousness post, but things are a mess and I'm feeling very lost, and I just need to write it all out.

Back in February I got a new flatmate, B. We got on well as people and two weeks later she asked me out. I said no, thinking I had no feelings for her. As the weeks went on, I started to grow feelings for her, but for me this was a confusing time because I have never been in a relationship before and so I had no real reference points as to what was going on. I didn't have a crush on her, but I did catch myself wanting to be physically affectionate to a degree which I wouldn't with friends and our friendship became increasingly awkward. In addition to this, my brain said to me, "You can't date her anyway because you have doubts about your sexuality and your gender identity as a straight, cisgender man." Which was true, I totally did. I've questioned seriously on and off for the past four years without getting anywhere. Our communication has always been good, and we've talked about a LOT of things. She encouraged me to do my emotional homework and work out where I stood, whilst also saying that for her it didn't matter whether I identified as a boy or a girl because she's bisexual (B, if you are reading this, I've outed you because I didn't know how else to put it succinctly). This also explained why she asked me out in the middle of a period where I was a walking glitter explosion. When we were talking my mouth would open and suddenly the floor would be covered in Skittles. Everything I said and did screamed "If not gay then at the very least bisexual".

Eventually things got to the point where she challenged me on whether I was being honest with myself by continuing to deny my apparent feelings. I admitted this was a fair accusation. At this point I hadn't entirely resolved my gender and sexuality questions; however, I had felt a shift to 100% female combined with feeling wretched and angry that my body stopped others seeing the girl inside. I'd had an extended talk with B about this and she had reaffirmed that she was accepting. I took a leap of faith and decided that I did love her and in accepting that I did, I was able to accept that she loved me and that it was okay to be not cis or straight. We started dating. Two nights later I flew out of the country for a month-long holiday to see my family on the other side of the world. This had been planned for nearly a year. Two weeks after I returned I came out to her as pansexual. A week after that I came out to her and a few friends as a mixture of bigender and genderfluid (both a boy and a girl but I also slide anywhere between them). I was stoked, not only because it felt right and accurate, but also because it explained a lot of things, put various insecurities to rest and also meant I now had the mental and emotional space to start thinking of her and not myself. I even have a little spreadsheet to monitor my gender fluctuations.

That was two weeks ago. I thought that was the end of the major niggles, but now we've hit another road bump: I'm not spontaneously affectionate physically as much as I feel I ought to be and as much as she needs me to be, and she's currently feeling very insecure about whether she is enough for me, basically because I don't show affection. I've tried. I don't understand why I can't do it. I'm a romantic - this sort of stuff should be natural and it totally has been when I've had a crush. When I kissed her on the lips (not a snog, just a peck) I felt nothing. If I examine my heart, it feels like all the affection is there but it's fenced off. If you'll forgive me quoting Frozen, love is an open door, but it's locked and I don't have the key. Nor do I know where to find it.

I really worry about B. If I can't love her, then we need to break it off and she needs to find someone who can. She's amazing. Not many people would realise that their potential boyfriend isn't straight or cisgender, encourage them to find out who they are, and then go and date them anyway. She's also fiercely bright, we have a truckload in common and she is kind and caring towards everyone. Oh, and she's really pretty as well. I feel I won the girlfriend jackpot, but I feel terrible for her because she doesn't deserve this. If anyone has earned my affection, it is her. She has been far more patient and understanding than I could have ever asked her to be.

I meant to write this thread asking what the potential pitfalls are when a non-binary (am I allowed to use the word "trans"?) person dates a cis person. I don't feel I've changed as a person much as a result of determining my gender, and as such I didn't think it would have any effect on the relationship. She told me one ramification for her is that she will always have to deal with people saying to her, "I think your boyfriend is gay". But in writing this post I've realised that really there is a much, much bigger problem, and that is that I simply don't know how to relate to her. I mean, I kind of feel like I'm back to square one with all my social skills. Do I have to date her like a girl would, or like a boy would, or both? What does that even mean? I don't even know how to be a girl during the times when I feel I am one inside! How can I have a relationship when I don't understand what I'm trying to do? It's like having two jigsaw puzzles: the "boy/girl relationship" jigsaw puzzle and the "girl/girl relationship" jigsaw puzzle, except that I don't know how to complete either of them. And I worry for her as well. She says she can see that I'm a boy and a girl, though she hasn't observed the slides yet, but I kind of don't believe her. I've always thought I had a largely male way of thinking, and how is she going to reconcile that with what I say my identity is? Is she just going to come to the conclusion that I'm lying and making up excuses, and then dump me? :tears:

As you can see we have had a very weird and compressed relationship. It would take most couples much longer than the time we've had to learn as much about each other as we have. I also suspect most relationships don't feature a double identity crisis for one partner right at the start. We trust each other. Our communication is great. I do care about her - if I didn't then I probably wouldn't be writing this. I just don't know what to do and why expressing my feelings isn't coming naturally.

I really want to understand her cisgender perspective as much as my own, so I can relate to her properly. Google has given me only a few articles here and there on cis/non-binary relationships. It doesn't seem to be something anyone talks about, and I worry that there's a whole shed load of potential difficulties which I'm just not even aware of, nevermind able to fix. Sorry for the ramble, but I'm quite upset at the moment. :tears: