Your assumption is that living in relationship with other people requires a live-in, romantic relationship. While that is the traditional view of stability, it's a bit old fashioned.

The modern world allows people to divorce or to never get married even, and those people are quite able to live very fulfilling lives. A person who has moved on to live independently and quite comfortably without a romantic relationship is quite capable of being stable, confident, very fulfilled, and even full of supportive, loving relationships - they may just not be what you consider as traditional, and they may not be romantic partnerships at all.

I think of my sister and both of her grown kids. My sister divorced in her 40s. She's pushing 70 now, and she has never been more confident, more happy, more full of truly personal and close relationships as she is now. Both of her kids are in their 40s now. Both of them are still single and I highly doubt either of them will ever marry. They are very independently minded, always busy with friends, organizations, travel, pets, etc. They are healthy, happy, and very much stable. They would definitely balk at being pitied or with anyone who thinks they must be missing out on hugs or closeness in their lives. They definitely aren't.