Our whole relationship is a lie

Me and my boyfriend's sister (let's call her Jacklyn) have had some conflict since March over something I didn't do. We talked it out and solved it, a few weeks later she started it up again for no reason. This time it was worse because she involved more family (family that aren't living with us and haven't met me yet) in it and told them things about me that weren't true. Btw me, my boyfriend, his mother & father, older sister, her daughter and fiance all live together. My boyfriend's mother set it up for us to talk the night before last and Jacklyn half assed apologized for being racist towards me and so on. Then we talked about other stuff and I asked why our relationship isn't as important as Jacklyn's and her fiance, she proceeded to ask how long have me and my boyfriend have been together. Me and his mother say about a year and she laughed and started to say things like how he doesn't want to be with me and how he said he kinda wants to be single several times throughout our relationship (so she sees our relationship as a joke) and she clearly said that to hurt me and it did.

So I said fuck trying to talk things out with her and left and my boyfriend followed behind. I asked him if it was true and he said yes and that he was scared of commitment but he apparently doesn't feel that way anymore. I asked him if there was anything else he wanted to tell me before I found out about it. Then I found out he went on a date with a girl on what I thought was the first month of our relationship. I asked who was it and he told me.... It was DAijah, someone I noticed in his phone before and kinda expected something from. Me and my boyfriend have talked every single day since our first date so pretty much we were all romantic and shit with each other but he still didn't see me as his girlfriend I guess. Apparently they had still been friends and communicated throughout our relationship, he admitted he deleted all of their conversations because he felt guilty and didn't want me to see it and bring it up. He thought we'd never have to tell me about it and since he felt so guilty he kept treating me out to stuff like dates, dinner and taking me shopping just to make himself feel better about the situation. I thought he did those things because he was good boyfriend and wanted to. I feel like our whole relationship is a lie and that he'd always be honest with me. We've been so excited to do something for our one year anniversary but now that date means nothing to me, I don't want to go or do anything special I can't even look at him the same anymore this is not the man I thought I was in love with.