As some others have said, I think it does depend on whether or not living alone is a choice, as well as on personality type.
I’m not living alone but I am the only adult in my house since DH died. I’m both very lonely and absolutely exhausted from solo parenting, grief and from being the only one earning an income and looking after the house. DH was wonderful company and pulled his weight with house and kids and enjoyed doing so.
But I can’t imagine living with another adult now. Over the past couple of years I’ve redecorated and got a new life routine I guess. I’d love DH to come back, see what I’ve done with the place and fit right back in - but I don’t think anyone else would ever fit. Time will tell, I suppose. I am fearful of the future when DCs move out, but I’ve got another decade.