I relate very much with some things you talk about. For a very long time I had troubles with feelings of love, feeling strong feelings at times for a person and then seeing those feelings disappear completely. When a girl showed she was attracted to me I was often afraid that my feelings for her would disappear at once. I still had that problem in my most recent relationship, in the sense that my emotions were sometimes not super strong, and I worried about it, but it was nowhere near when to when I was a teenager, where feelings would disappear completely. Anyway, I have read some other people here who said that they didn't even feel anything for their children anymore sometimes, which must be frightening. Perhaps it is indeed related with DPDR. (In my case I actually think that my suffering around love could have at least partially caused my DPDR as a protection mechanism against too strong feelings in that area, because it was really hard at that time. I now identify with the characteristics of "sex and love addicts anonymous" by the way).
What helps me to worry less about it is to try to accept what I feel or don't feel and try to be honest, just as you did with your partner. It's very nice that she is understanding.
What I experienced with DP is that everytime it happened strongly, I had the impression I would never remember my true identity again, that "I" was an artificial sensation that was now lost forever. But when the DP was over, I could feel like myself again, exactly like before, and that DP episode was the thing that now felt artificial and fake (although terrible). These past weeks I have felt some DP again and I have tried to remember that it was all artificial, although it doesn't feel like that at all. I try to remember that I am just being kind of (very?) unpleasantly high and what I feel doesn't reflect reality. Perhaps there is something like that that could work for the feeling of absence of love. What can hurt is to try to imagine why we feel like that, like "does it mean we should not be together, that my love was artificial?", or "does it mean I have lied about my feelings before?" or "will it last forever?", just like we (or at least I) can imagine when feeling DP.
Part of what hurts me in these feelings is the loneliness that I experience with them. During strong DP episodes I think I am very afraid of being abnormal and that people won't relate with me anymore, and that I won't be able to have nourishing relationships again, even with my family. Sometimes I think that if everybody knew about DPDR (not that they should) it would be much easier with respect to that. I could tell people "Sorry I am just having a DP episode now" and they would say "oh I see, don't worry, I had one last week", and I wouldn't worry that my reactions would be misinterpretted or that I would be rejected. Really, I feel that for me a big part of the problem and the anxiety around DP is the fear of not being understood or related with. Is it similar to what you experience?
Anyway, I would be interested to know what comes up with your counselor, if you don't mind sharing later.