I've been let down by every woman I've loved but once. Didn't expect it to affect me like this. Advice?

I didn't expect writing this to make me cry but my hands are shaking and tears are streaming down my face. I've got a feeling I might need an hour to compose myself to finish writing this post. I'll give you some back story, and then get to the point.<br><br>My mother abandoned me when I was 3. She didn't completely abandon me, I saw her maybe once a year and she'd pretend to be excited to see me but then ignore me for the rest of the visit. She'd buy me shoes that were too big and shirt that were too tight. She'd always say "this will fit you in a year" as if that was some kind of an excuse for not knowing my size, but my dad would buy me a new one the next day that fit right. She was never there on my birthdays. My dad was always there for me though. I tried to ignore my mother but it was hard. I felt like I must have done something wrong as a child for her to treat me like that. One day when I got a bit older I told her how I felt and she cried and promised to be a better mom. And she was for a year or so, until she disappeared again. This went on for years, me opening up to her and her promising to change and then not seeing her again until I was 13 and she came to visit and told me she was getting married and that I was welcome to come to the wedding if I wanted to but that she wouldn't expect me because she knew I didn't see her as my mom anymore. I didn't go to the wedding, I didn't care at that point. I had no siblings, my dad had a sister and that's it, and she got married and moved across the country when I was 7. My father died from a heart attack when I was 16. I was crushed. He was my best friend and he looked out for me my whole life. He was always there for me. I think I blocked out some of the pain of his death by going into survival mode. I was lucky enough to have saved some money from mowing lawns and selling candy in middle school. After spending a year being homeless I got myself back on my feet and went to college and got a degree. I got a good job now and I've been working it for 5 years. I'm sad to say it took me getting in a good spot in life to really be able to process my dad's death. I'm 27 now and until 6 months ago I still hadn't cried about it. I got a call from a number I didn't know last year, it was my dad's cousin. I didn't even know he had a cousin, he never mentioned one, but somehow they got back in touch. He told me my dad's estate was finally settled and that I had inherited some money and that I should come by to discuss the details in person. He was on the other side of the country so it was a trip but I decided to go. As I was walking out the door my girlfriend told me to be careful on the trip. I remember thinking that was strange, why would she need to say that? I get to the city and there's some woman in my dad's house. She's probably in her early 30's, looks a bit young to be the cousin's wife so I ask her who she is. She tells me she's my dad's cousin's daughter, and from looking at her face I could tell it was true. But then she told me she was also my half-sister. I didn't know what to say, I tried to play it cool but I think it showed all over my face that I was upset because she immediately apologised and then left the room crying. I tried to go after her but the cousin stopped me. He sat me down and told me my dad had an affair with his wife while they were still married. He forgave my dad and they remained friends, but their friendship suffered. They had a kid together and that kid was the girl I had just met. He said he knew my dad had died and wanted to let me know I had a sister but didn't want to disrupt my life. He said he had been watching me from afar and was impressed with how I had turned my life around and thought it was time I knew. Then he told me he and his wife had both died. They had a car accident years ago and left their daughter alone. My sister was 11 when they died and their siblings took turns raising her, passing her around between them. Her name is Lily and she didn't have a happy childhood until my cousin took her in recently. He said she had a bad childhood, that she was constantly uprooted and felt like a burden. He said she had a hard time trusting people but that I shouldn't take it personally. I think I zoned out for a bit but I remember him telling me the address of the will reading and that he'd see me there tomorrow. And then I left. I didn't want to leave Lily like that, I should have let her explain, I should have stayed and been supportive. I didn't even get to meet my cousin's wife and kids. But I just left. I went to my hotel room and cried. I knew I had a sister but I never got to know her until I was an adult. How could they keep her from me? My dad and I were like best friends, why didn't he tell me? He always said family is most important, but he didn't care about his daughter? I tried to go to sleep but my mind was racing with all the questions I had. I was debating on not going to the will reading and just leaving but I could imagine how I'd feel if I didn't get to say good-bye to the only family I had left so I decided to go. But I told myself I wasn't going to stay, I'd hear the will and then fly back home and never look back.<br><br>The will reading was simple, my cousin had inherited some money but he said he'd already been handling my dad's estate for years so he knew exactly what he was getting. Lily was also left some money, but I didn't pay much attention, I was too busy staring at her. She looked so much like my dad but she didn't look like me at all. She had brown eyes, I have green. She had blonde hair, I have black. She had tan skin, I'm pale as snow. She was short and had a small build, I'm tall and have some muscle. I was always insecure that my mother didn't love me but at least my dad loved me, now I felt like maybe I wasn't even his child. That thought didn't last long though, I remember my dad's face and the way he'd look at me with pride. Lily caught me staring at her but she just looked away. I tried to talk to her but she'd only give me short answers. I tried to pretend I wasn't hurt but she could tell. I don't know how long we'd been talking, but I knew I had to leave soon and I might not see her again so I decided to open up. I tried to explain to her how I felt, that I wasn't mad at her but that I had been let down by every woman I loved. I told her I just wanted to know her and be there for her and be family to her. But I could see the walls around her and I knew she wasn't going to open up. I remembered my cousin's words and decided to give her time. I told her that even if it took years, I was willing to wait for her to trust me, that I wasn't going anywhere. I gave her my number and asked her to call me whenever she was ready and left.<br><br>I was expecting to come home to a "how was your trip" text from my girlfriend but instead I got a text saying we needed to talk. I tried to call her but she wouldn't answer. I got home around 10 pm and she was sitting in my living room. She told me she'd been sleeping with her boss for a couple of months and that she was leaving me. She packed her bags and left. I didn't even cry that night. I don't feel anything about her leaving, it doesn't feel real. I keep expecting her to walk through the door but she never does. It's been 6 months since that day and I haven't heard from her since. I think about Lily a lot but I haven't heard from her either. I gave her my number but I don't think she looked at it. I've been thinking a lot about my dad too. I don't even know what I think about him anymore. He was my best friend but it feels like a lie. I'm starting to think I was stupid for opening up to Lily like that, that I should have just left her alone.<br><br>Advice?