I really have no idea what decision to make?

Daniel was my best friend forever, then he asked me out. We dated and he was my first love. I can't even explain how he made me feel, but we broke up. I was really depressed for a long time. I couldn't find anyone that made me fee the same way. After a lot of arguing, Daniel and I went back to being best friends. I feel so comfortable around him. People think we're dating because apparently we flirt a lot. We sort of disreguard it, but we know we're perfect for eachother event though we won't admit it to the other. One of the reasons iss, Daniel has a girlfriend. The thing is, they're relationship sucks because she's really into him, but he's not really into her. He still likes me and will tell my family, but not me. Recently, I met a guy, Matt, and he is sooo sweet, amazing, and handsome and I like him a lot, but I constantly find myself thinking about Daniel. And Matt is in love with me. I'm not in love with him even though I thought I was. I do like him a lot. But Daniel and I definitely feel for eacother, but we don't want to hurt our boyfriend and girlfriend. It's only been a couple months with Matt, though. Should I hold on and wait for my feelings for him to grow (It's not like he did anything wrong), or should I break up with him and go after Daniel??