Disappointed

He had to leave, to go back home due to some medical issues. I spent 3 days alone. He texted  me on the day he left, later that night, that he was all right and that he's going to bed. At that moment I wanted to reply: "Really? You mean going to bed with her right?!?" I didn't reply. I haven't heard from him until Saturday around midnight. He was getting very worried that I didn't send him any message, that I didn't left him any offline messages, emails etc....Why the hell would I do that knowing that you are in her arms and that you're spending all your time with her. I couldn't bear to hear another lie from you. I felt abandoned, cheated, unimportant....
When he came back home on Sunday night I noticed he had a new sweater. I asked him if he bought it, and he told me that it was a Christmas present. I asked from whom it was, and he smiled telling me that he couldn't say. All he said was "It's from a girl." Then I told him that this clearly means that it is from her. He tried to deny it but I'm no fool. He acted like he did nothing wrong.
I have this mix feelings....Sometimes I just want her to know what a liar he is and all the terrible things he did/does, sometimes I'm telling myself that it is not worth it and just let it be, sometimes I feel like I wanna get the hell out of the room and never come back, and sometimes I feel the need to just hug him and be hugged.
I always say that the wheel always spins and sooner or later we all pay for our actions.