How to be more kind to myself?

hi everybody, first time posting in this sub. I'm someone who's always struggled to feel totally secure in relationships, im about to turn 33 and the longest relationship ive had is 2 years. I've noticed that when I'm really interested in someone, I get to a point where my anxiety becomes larger than the good feelings that I should be feeling, and I think I self sabotage and talk down to myself about what said person might be thinking/feeling.

I'm not sure whether I just haven't found someone who meets my specific needs or if there's something unhealthy about the way I feel and process emotions. It's got me feeling really down because I want to improve myself, but even through therapy, I'm finding that difficult and still struggle to put the things I know I should be doing into motion.

any help on people who have had similar feelings or experiences would be much appreciated.