Back to the topic, as a female Aspie with a male partner who seems to be equal parts NT and ND:
Men don't seem to be so needy in shows of affection, and in my experience, they tend to ask for practical things. Most women have been tricked into believing there are armies of Prince Charming waiting for them, and have a hard time coming to grips with the reality that no, men aren't here to cater to their every whim.
I don't buy into the "Aspie male" stereotype with all its mentions of how mysterious they are supposed to be. I think there is an unhealthy romanticization of their standoffishness, as if the "emotionally unavailable" characteristic often encountered was a puzzle that needed to be solved at all costs, and I think it's a disservice to everyone involved: the Aspie males who are all put in the same bag, and the NT females who expect a one-size-fit-all solution straight from the textbook. It's really important to keep in mind the diversity of thought and reaction even among the neurodiverse crowd.
I'll put myself in the shoes of the ladies asking for advice here, and for the sake of the exercise, I'll take into account my longtime boyfriend's ND traits: have I ever felt that he was not showing love? Yes, when I considered that showing love was giving me items A through Z of a particular wishlist of "expected romantic behavior". And I thought he was being a total a**hole for refusing to give me those. And one day, I realized how much we were alike. I started looking at him through the same prism as myself, and that's when it occurred to me: he shows love in his own way, and that's all that matters. His shows are through the problem-solving, the bag of chips he brings me home when I need comfort junk food, the care he takes of my cat when I have a panic attack, leave in a hurry, and forget about the litter, in spite of gagging at the smell of cat dejections, in the cab he pays for when I have to be outside late and plan to just look tough outside on public transportation. Is it romantic? Not really. But it shows he cares & want to protect me (and possibly clog my arteries). I became much, much happier when I let go of the expectations of love that are ingrained in our brains since childhood, from fairy tales to movies to soap operas (I'm not saying you should strive for no more than potato chips, though). I found peace of mind when I stopped comparing my relationship to those of my coworkers who were NT+NT (and being the one person people somehow always come to for advice, I've come to learn that they aren't all that happy). When you're asking for help in any field from someone, you usually have to accept it's going to be on their terms because they are the ones doing a favor. It's the same when you're asking for displays of love: love will be displayed, and it may or may not be displayed as you hoped. But what matters the most? Love displayed in an unsettling but genuine way, or love displayed in a familiar, but totally artificial way?
To the NT ladies, maybe your Aspie male partner won't remember your birthday. Or send you roses. Or even let out a friendly groan to show he's listening. Maybe that partner won't double as your best friend, and you'll need to find a best friend for certain purposes (don't put all your eggs in one basket, anyway). Maybe --very likely-- he won't be able to change, or at least not in the proportions you need, and you will feel that you're doing all the effort. Relationships aren't about counting how much effort one does vs. how much effort the other does, it's not a competition. But he's probably there for you all in different ways; learn to focus on those. If it's an atypical relationship you're trying to nurture, should typical expectations and codes really apply?