I know it's none of my business and so I am probably am being unreasonable.
My brother is 32, and met his DP when he was 21. So, they've been together 11 years. In that time, they've been on holiday once to Bournemouth. They've been engaged 8 years with no sign of a wedding. They don't appear to planning to have kids (although they always said they would like to), his DP is 38. They've both got obese (i mean that literally)
I believe that they were both first boyfriend-girlfriends and breaking up a serious relationship (perhaps in your 20s) gives you the confidence that things will be ok in the future.
I just see a seemingly unhappy loveless couple and I feel so sorry for them.
I wouldn't say anything and I should keep my nose out.