Our capitalist society places huge emphasis on heterosexual monogamous relationships because they're the most essential for the reproduction of labor power and as a result it's become increasingly hard to find the sorts of social support and validation that used to come from having a bunch of different kind of relationships and living in a community.

One thing that can help with that feeling can be trying to find something to do that doesn't put romance front and center - community band or choir, trail work parties, community gardens, dancing or fitness, sports teams, etc. Having a shared goal can reduce feelings of isolation.