I’m not sure how much you can change from being insecure
You have to recognise that you don't need to change. It sounds backwards, I know. But there's nothing wrong with you. Perhaps reword it? It's not that you're insecure, it's that you like a lot of emotional contact with your partner. I had to do this. My anxious attachment style had me trying to attach to all sorts of unsuitables, and then finding fault in myself when the relationships went wrong.
But the thing is, it's all about your relationship with yourself. We get anxious when we're not sure what's going to come up, or that we will be able to deal with it. But when you realise that, if everything went wrong, you'd have to fall back on your own care for yourself, the quality of the care you provide yourself is crucial to feeling safe.
You have to look after yourself as if you're a child. It's not just 'eat right and get enough exercise', it's taking yourself out to do nice things, making sure you put enough stimulation in place to make your life happy, having your back in arguments, making sure you don't spend time on bullies, making sure you feel you have agency etc.
You don't have to fix your insecurity, you have to recognise that you've got this. What ever it is, you've got it. You can handle it. Being single? It's not bad news, because you know exactly how to do it in a way that makes you happy. Right? If not, what makes you happy? Go do that. And if the only thing you can think of is 'having a boyfriend' or 'going on dates', then broaden your interests.