Can a good relationship come from a 3some

I was in my last relationship for 3 years. I met him in high school and had only had small meaningless little flings. I lost my virginity to him and in the midst of my cruel mother divorcing my dad he was there. He would sneek over at first then it become obvious he was staying the night till eventually he moved in. I found my self 16 and living with my boyfriend. My father didnt like it but he let It happen anyway. All the alone time made me realize, he was an ass. All he ever wanted was to smoke weed, and watch porn behind my back. We would fight all the time so I found myself so stuck because he depended on me and my parents all I wanted was an escape but was too scared of a life without him. I was young, and already comfortably numb. Till my boyfriend found a new friend, we would go over to his house and hang out all the time. He was a smart guy loved playing board games was interesting and I found him attractive. Eventually we heard this mans stories of the orgys he's been in and all his crazy past. It freaked me out a little but he seemed a nice guy and ha sadness behind his eyes. One night we were all laying in his king size bed watching a movie and all of a sudden the 3some started to happen. After a few months of this odd living situation want-to-be 3 person relationship came crashing down. The man would stare at me as we were all laying in bed at night. We started to fall I'm a forbidden love. We then had our first night alone together and my boyfriend came back from work to find us naked watching a movie. He lost it in that moment it was too much so he wanted it to stop and for me to leave with him. But I wanted an escape and this man promised I be my hero. The flash off a small amount of times memories ran through what I would lose. The poems he snuck me, the songs we would listen to, how different he seemed, the age difference showed a level of maturity. I just couldn't leave, but I felt so erong abandoning my ex. But I could leave I was torn left with my ex because I felt so wrong and ended up running back and finally leaving my boyfriend, I moved in with him because I got kicked out of my parents house because me and my mother dot get along and I had nowhere else to go. He took care of me I'd cry I moved in to soon I shouldn't live with him we had sec and don't really know each other it's all too fast and would sob of being a bad person for what did. After being sad and getting over it trying to be happy he was by my side trying to help. And eventually things reached some sort of normalcy and I begin to get to know him. Almost a year has gone by and we have fought had ups and downs and the other night he revealed a truth. A truth that he is a liar, most of what he said who he is are lies. He has never been in orgies and so many small things he said was true wasn't and I would question all the time andante him explain the situations cause I was interested in his past and he'd just lie. I feel so confused I know he has drinking problems and isn't as romantic as he was. Also exclaims repetitively that he is a narcassist. But he's smart, most of my family likes him which says alot considering my family is not normal, I can tell I'm important to him but he showed it the most trying to get me. I have told him show me your romance he says he isn't really romantic. I tell him try and he try's to then it fades away. I feel like I've made the same mistake again and don't know what to do. I love him but there's so many small things and lies he keeps asking me why I stay then and I just say I love him I don't know. I can't decide if I should Tay to see him hold his promise of not lying like that again. Because guys lie about who they sleep with and exaggerate alot there's worse things. But I don't want a three yet waste on someone who turns out to e a complete dick. I don't know what to do.