Any tips on how to actually stop ruminating

I'm AA and my bf has secure attachment.

My bf treats me well on a normal basis. If I were to ask for reassurance he would surely provide it, he always makes time and effort for me.

However, sometimes he gets busy with work and I feel that I'm being neglected and it sends me into a loop. I will have a running internal commentary on how he will forever prioritise his work and neglect me in the future and I'm just his girlfriend because he needs a girlfriend, not because he likes me.

Subsequently, I will start showing protest behaviours and I will think about toxic ways to protect myself such as leaving the relationship even though everything is going perfectly fine.

It's actually insane how deeply I will think about different things and escalate the entire situation in my head. However, I am also aware that these are my anxious attachment "thoughts" but part of me feels that I'm used to the drama and I subconsciously like to indulge in them. It's always so hard to stop thinking about it.

How do you guys cope with such thoughts?

Thank you <3