Well, let's just say that couples assume that someone who is unattached must be wishing to "meet a girl." Like my nephew's wife. She's older than I am, and a while back, when they were living in South America, she insinuated that if I joined them down there by the equator I might meet a woman who I would go goo-goo ga-ga over. These weren't her exact words, but the idea is that she wrongly assumed I was looking to become attached (emotionally entangled).
I'm not denying the sexual attraction I feel for exotic women. What I am denying is any desire to seek some kind of fulfillment in satisfying any such desires. I just instinctively understand a couple important details: (1) that such attraction is rarely mutual, and (2) what I need to endure this life is already within me and, for me, seeking wholeness in a romantic union with a woman would mark a step backwards for me.
I've made it clear to myself that I may be better off alone without having to deal with the demands of another human being (and her relatives!).
So, that's one aspect of interacting with couples that is off putting, that unspoken assumption that the single man can't possibly be "complete" without a significant woman to make him "whole."
Although I have not spoken to my one cousin for nearly 10 years, I recall his asking me in front of his wife when was the last time I "had any". I told him, at the time, that I gave myself an orgasm that morning. You see, he and she assumed wrongly that one had to have a partner to be a sexual creature.

Anyway, I'm not exactly comfortable discussing just what I find so off putting about conversations with couples. There's just something not quite authentic about the discourse. Couples may be forced to share certain beliefs or attitudes just to make for peaceful cohabitation.
There's also a feeling that the couple is at liberty to just be goofy as a way to not really take anything you say seriously.
I'm sure there's more to it which I could elaborate on, but I would prefer not to at the moment.
I'm enjoying a certain detachment from such concerns.
It's wonderful not to feel pressured to "do anything," to make some kind of "impact" in the so-called "community," to learn how to sustain some kind of relationship which one might be better off without.
There are those who will say I am less of a man for not having "love" in my life, and yet I have had to learn to accept myself unconditionally, and this means that my self-worth is not dependent upon any significant person's momentary judgments of me.
All we can do is live and let live. I don't have to sustain bonds with couples. I used to visit my cousin years ago until I brought the wrong color and type of woman along with me. Ever since then, even though it was many years ago, I suppose many callous and petty attacks against me have been made behind my back. I sense those kinds of things, and so, in order not to be hurt by their judgments, I just don;t give a fuuck about what they think - in turn, I totally detach, as though they are strangers, which, after awhile, they do become.
We do not choose our families, and while there are those who I may have cared about, and still do, at the end of the day, we get through these days, through this life alone. Even those who consider themselves married and bound to another until death do us part, they are still, subjectively, alone.