um, yes that level of anxiety would be alarming to a partner. Yes, it would be absolutely devastating to loose a partner, but we also need to know with confidence that we can and will survive and make a life without them if need be. The knowledge that the partner could not cope without us is a very large burden to place on a person.
I have to be honest and confess that I stayed in a marriage far too long for this exact reason - I knew he would not cope without me. I know now that it's a red flag....perhaps not an all-out dealbreaker, but certainly not a tick in favour of continuing with that person.
For what it's worth, I also get anxious when hubby is out drinking and doing heaven knows what. But I NEVER confess how I feel to him. Why? Because I'm being irrational and have no business putting my irrational behaviour on him. And I also know that while losing him would be a terrible, terrible thing...I could survive without him.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.