I'm just trying to get past all of this

I'm just struggling so hard with co-dependency.  It has totally ruined the relationship I'm in, I can see it, and I know it, but for whatever reason my fiancé is still here.  I'm so reliant on her for my  happiness, like somehow her approval, and her love is the only thing keeping my heart beating.  I don't know what to do.  I'm seeing a therapist, and I'm going to start in CoDA meetings...  I just want to get better.  I don't want every conversation that she and I has to have to center around my insecurity and constant need for reassurance.
I went on vacation with my son a few weeks ago and spent the entire time upset and miserable because I wasn't around her every second of the day.  I spent money buying her things to validate myself because I just don't feel like I'm good enough.  Like if I don't buy her gifts to keep her in my life then there is no way she will want to stay.  I just feel so ridiculous.
If anyone has any kind words, or advice, I'm all ears.