I guess that's the side effect nigh immortality, you are always painfully reminded that unless you off yourself, you're probably gonna outlive everyone you know and love and end up alone... And you also probably have a hard time adapting to changing times since the world you live in is vastly different to the one you once knew. I dunno, am talking out of my ass at this point, tho it would be interesting to see him really having a romantic relationship just to time tear them apart (not saying it would be fun to see it, just interesting to see how the author would portray such happening in his life and how Aesir could deal with the grief).