I'm musing on this concept way too much.
I think it's because I'm 37 and long-term
single and I've just realised that saying "boyfriend" out loud now does feel a bit silly. Equally, I think I'd feel a bit daft saying, "I'm his girlfriend" now.
Yet, I wouldn't co-habit or have children with someone who had no intention of marrying me. If I got to the 18 month stage, I'd either be expecting some firm plans for the future or a break up to free me up to meet someone else who would be serious about marrying me. But at that point, it's a bit hard to keep referring to someone as "the guy I'm dating" or "the man I'm seeing".
I'd probably end up going with just his name. Or the cringeworthy "person/man I'm with". I can see how other frequently annoying terms have made it into the vernacular.
"This one"
"The missus" (seemingly used by every unmarried tradesman I've ever met)
"My other half"
"My old man"
"My fella"
"My ladyfriend"
"My person"
"My gentleman friend"
etc
I think it's just another symptom of how society has changed now that people marry later, don't marry at all or have numerous long term serious relationships throughout a life time. We don't have enough words to define these relationships.
Even on forms now your options are;
Single
Married
Divorced
In a Civil Partnership
Living with someone
Prefer not to say
Someone in a two year relationship with a person they don't live with has nothing that really applies to them.
When I was a child, "partner" was most commonly used by people who had same sex partners. My Dad had a male business partner and I found out that quite alot of people thought they were a couple purely based on their use of the word partner!
I've got quite alot of LGBT friends 20s-50s in long term relationships (one couple together as long as I've been alive!). Every single one of them uses "boyfriend" or "girlfriend", with pride.