How to say "I love you"????

Okay, so my boyfriend, we will call him 'C', and I have been together for 5, almost 6, months now. We met about 3-4 years ago, when I was a junior and he was a senior, in high school. C has always had a crush on me since we met, that I knew of, but pretend not to know. However, at the time I was dating this one guy, we will call him 'X', who treated me horribly and I could not seem to break away. X is a sociopath, and proudly admits it, so he is quite charming and manipulative, and even though I knew it I just couldn't seem to leave. He always convinced me to stay. Somehow I stayed with him for 3+ years...

However, after C graduated, he kept in touch with me. We never ever saw each other in person after that, at least not for another 3 years. He was always there for me to text or call when I needed to vent, cry, etc. X use to taunt me when I tried to confide and cry to him. Tell me he doesn't have time for my emotional bullshit and has no clue how to deal with it. So I held everything in around him. Did everything he said...

Thankfully, X got accepted to a university one state over and we ended it. The break up went quite smoothly actually. No arguing or fights. We just agreed it was best. Of course he waited until he moved to tell me over text. 

The next thing I knew I was so happy and so relieved. I maybe cried for a few hours, but then the relief hit me. I was trying to decide what the first thing I wanted to do without X was. It then hit me. I haven't seen C in years and he has always been such a good friend and has always been there for me. 

So we finally saw each other, I was so happy and so was he. It was crazy how much we have changed since we last saw each other. We hung out a few times the following months after that. Then one night one thing lead to another and you all know how the rest 🙄. We decided to be together afterwards. He was so ecstatic to finally have me and I then realized that, as cheesy as this sounds, he was there all along. And it now feels so incredibly good to finally have someone who gives a shit about me and thinks the absolute world of me.

There is just one problem. I have no clue how to say 'I love you' and I am scared too. I know he loves me and I'm confident in that. I think he is scared to say it too. It seems silly. We are in our 20's and acting like children. I know he tries to say it and then seems to "chicken out", but I chicken out too so I'm not judging him. 

How did you all say "I love you" for the first time? Suggestions? I know this should be easy thing to do, but for some reason I am scared!