There is one common denominator in your failed relationships ...you.
If you ain't willing to change for a good love...
You may be better off alone.
"Failed relationships"? I have been involved in several wonderful relationships that eventually terminated for one reason or another.
That they were not "till death do us part" is no indication of "failure." Those were remarkable women and our time together was rewarding and fulfilling. Some stay in touch at least occasionally (one from fifty years ago).
We each went on to other adventures and other relationships -- but still think highly of each other and "are there" for support or an intelligent conversation.
Failure? I don't think so.
Regarding "change for a good love": I absolutely do not expect anyone to change substantially in order to be in a relationship with me and I damn sure am not about to change anything important. Little things I might consider -- and did stop smoking my pipe at a lady's request on two different occasions -- once for 25 years and once for five.
Should one take up religion, or become an animal lover, or "dumb it down", or become sedentary to entice someone into a relationship?