Arguing with my boyfriend over ridiculous things

I am 18 and my boyfriend is 38..I know that might come as a surprise to some of you but this isn't why I am here! Me and my boyfriend tend to argue a lot over so many ridiculous things. I am writing this because I want a second opinion on some of the things he thinks I do wrong. For example the latest thing is he has gotten angry because I sent me driving instructor a text saying I can't make it to the lesson and i put a smiley face ' :) ' on the end of the message. My boyfriend is fumming because he thinks that this smiley face means something... he said i wouldn't have sent it if my instructor meant nothing to me. He also said that me doing this is like cheating on him. He seems to think there is something going on with me and my instructor which is ridiculous because I would never do that and the only texts we have exchanged are me saying i can't make it to the lesson and him saying the cars broken down so the lesson had to be canceled! I don't even know my instructors name yet he still thinks something is going on. There are so many stupid things we have argued about and today I got fed up with him telling me what a bad girlfriend I am and I want a second opinion from someone who has no idea who I am. So please, can anyone tell me if they agree or disagree with "It's ok to text my driving instructor with a :) on the end of the text. a :) does not mean anything" I know it seems really ridiculous but I just want some reassurance that he's the one being ridiculous not me. Thank you.

The 20 year age difference will always play apart in how you see things and how he sees them. His insecurity is really what behind this. He's almost 40 and you haven't turned 21 yet, I believe he will always see any man as a threat.. Anyone in your generation would see it the same as you.. His generations no so much... Let this be a sign of what to expect.. And Yes you are here because you're 18 and he's 38!!! How did you guys meet?

He is very controlling and trying to control you. If you allow this it will continue to get worse. He needs to see a counselor or you can go together. If not, I'm afraid you will become a sad statistic. Hopefully he doesn't turn violent, but it sounds like without help, he may progress down that road. If he doesn't trust you, then it's not going to get better.

I agree I am sure he is insecure.We met because we use to work together. He can be controlling and at first he use to try and be controlling. I never let him think he's 'won' during an argument and I will never change my opinion on what is right and wrong just because he wants me to. He says he trusts me but if he did then I don't see why he should get funny about ridiculous things like this. He also says that the reason why we argue is because he misses me as sometimes it can be difficult to see each other.