REGRET, why do i do it?

Hi, im really confused im not sure why i do this, i keep geting at points where im at the brink in making a meaningful and possibly long term relationship with girls, and whenever i reach this point i just break it off not sure if im getting nervous or anxious and i regret it like crazy once it is already too late, to repair the damage im 27 and i have had almost zero relationship experience, and it's not like im even having with these women, the furthest is a kiss and its only been twice. someone ist me please?