im sad

I am going through a really tough time in my relationship with my SO, he is cheating on me I am sure of it. Sometimes I think it's in my head. But when he is constantly accusing me, when there is no reason to, then my thinking is he is cheating on me. Today I was sure our relationship was over, than out of no where he drops my keys off at my work, and I text him because I am in the back where he can't come, a security officer has to drop them off. So I take them, I am busy at the moment and I can't get to him right away and he is gone. So I text him. He calls me and tells me he is with my bro in law, and they are going out to the woods. Well he tells me he is sorry and brings me lunch. When he gets here we talk as if nothing happens, and he kisses me like everything is ok. While my mind is reeling from all the name calling and telling me I am cheating, when I am not cheating. I feel so hurt and sad that I love this man and he treats me like this. i feel like things are supposed to be great right now, because we are barely in this relationship a year and a half. I really don't have any one to talk to right now. Just DS. I can talk to my family and friends but they are all busy with there own lives.
So today he gave me a kiss and hugged me as if nothing is wrong. I don't know how to feel about that. I feel confused, and angry, hurt. I am trying to keep myself sane at the same time, instead of going all nuts and crazy on him. I feel like I am in a hamster wheel. I hope I can get things is  resolved. I will write more.