A tad bit confused

Goodmorning ladies:) So I'm a little confused about something a close ex said to me a few days ago. We have had a thing for years and still flirt and all good stuff, well he asked me if I wanted to know something funny and so I said yes, he said "By the time you're 18, I'll be out of the army" which isn't long at all, about 2 years. Let me state that he isn super older than me😂 well then he said "how does that make you feel?" Lol so I'm just confused as to why he brought it up, so I was hoping a someone could determine why it was brought up..