Date yourself
Spend time alone!
We have all heard that you can't love someone else until you love yourself.
I don't entirely disagree but it's such a strong claim. Loving oneself is very hard, and it's often the perspective of another that helps fill in all the gaps for us.
I don't think you have to get to "loving yourself". I do think you have to accept yourself.
You have to tolerate being yourself. You can't hate you, you can't be uncomfortable in your own skin. That will get in the way of an authentic relationship with someone else.
When I got divorced, I told my therapist I wanted to start dating again at some point, of course. And she told me, not until you've dated yourself.
Which is fair. And, tbh, is something I'm still doing.
If I want someone else to value me and spending time with me, it's worth knowing my own value and whether I'd want to spend time with myself. What do I want, what do I need, what am I looking for and trying to become.
It's hard to find the answers to these questions when we're enmeshed with someone else. Be it romance or family or friend.
You need to spend time alone.
Whether you're single or dating or married.
Spend time alone.
Date yourself.
Know what makes you you and why that's valuable.