You may not be afraid per se of love but of what consequences a relationship may lead to (when things get bad)
Your prior two relationships may not be what you ought to base your future expectations on. During the first relationship, you were quite young and inexperiences. The second relationship seems to have been a wrong choice from the start (you took a chance being with her and doing what she wanted (she was married)
It is not the dating or the love that you are anxious about. These can be remedied if you chose a compatible, uninvolved person who has the same interests and goals as you. Falling in love is not too hard. People can become infatuated fast. What keeps a relationship going is the common things you find in one another and how you treat each other.
Feelings originate in the mind. You feel what you tell yourself. If you mentally shut down, then you become emotionally numb. Instead, focusing on the positive things when you're with her, focusing on the present moment and not entertaining future problems would be where you want to start.