@imagypsytraveler – I was just going based on your description. You said that the feelings you have for this person are like those you have for a friend. You suggested that it’s not romantic and that there are no intentions toward marriage. If a friends with benefits arrangement is agreeable to the parties involved, then of course it could go on for decades.
You could call it a long-term relationship, and you could refer to him as your partner or SO, but to me, that implies deeper romantic feelings and a degree of commitment that is greater than what close friends share (regardless of whether they’re sleeping together). I’m getting a vibe from your most recent comment, however, that you might want it to be more than FWB. – are you sure the feelings you have aren’t romantic?
I am just considering classifications for the relationship. I was 32 when I had a FWB – I don’t see what age has to do with it. My elderly patients who are not married but bring the person they’re involved with to appointments often introduce them as their “friend” – the benefits part is implied.
Our society hasn’t really established good terminology for these situations. “Boyfriend” definitely sounds silly over 35, which is why my fiancé and I got engaged – we’ve been emotionally committed since our first date, and as good as married but without the paperwork since we moved in together. But describing one another as bf and gf felt awkward in our late 40s, so we talked about it and decided to get engaged to change the descriptors. We’ll get married eventually – when it is pragmatic to our lives; so we’ll be each other’s fiancé for years. You do what feels right and works best for you.