I I understand what your going through because I have recently gone through simiar experience of online dating and dealing with dissappointment after dissapointment when opening yourself emotionally, which I think comes from having expectation of putting your happiness in another person.

To answer your question, I think you can find lasting happiness in your life if that is what you want and focus. Inner peace and happiness comes from working on the inner world and not outer world.

Hope this makes sense and helps 🙂