Issues with my boyfriend

Hi my name is Rachel and I have high functioning autism I am also dating a guy who also has high functioning autism. We keep having issues with our relationship. When we together it’s great there a spark and we get on well but when we apart we have issues we don’t communicate properly and we then start arguing. He says he wants to do things like go out for a meal and so on but keeps putting it off this then causes issues as I get really frustrated with him in the end he snaps at me and says he not ready i don’t understand why he couldn’t have said that in the beginning. I’m 31 I’ve been in a few relationships he 42 and I’m his first and hopefully only girlfriend. I just want to know how can we work through these issues because I know that we can be a great couple if we just communicated better.