what do i do

So earlier i started talking to my bf and i straight up asked him if he plans to have children with me and get married eventually, which I feel as if i am suppose to be able to talk to him about this without it starting an argument seeing that we have been together for over 3 years of my life i deserve clarity. But he didnt even wanna answer the question but when he did he said he didnt know if he even wants kids. And then i said well you've known from the beginning that i would want these things eventually and its not fair to me. He proceeded to start talking over me and getting attitude and i was being as calm as possible and was speaking in my sweet voice, he kept saying i was trying to argue and i was not. I didnt cuss, didnt raise my voice once, i was soft toned the whole time. Then he said (because i had been on the phone with my bff earlier) that i "always wanted to start a fight when her and her man are fighting." Which isnt true because i never tell him when they are lol and the only reason he knows rn is because i had her on speaker today. But then i told him this had nooothhhinnng to do with my friend. It was about me and my plans and wants for the future. I wasnt saying we had to have a baby and get married today lol i would be okay with waiting a few years. But i just dont understand how someone ive been with for over 3 years cant even open up to me and talk about stuff like this. What do you think? I feel like i should be able to have a rational conversation about this without it becoming a problem or an argument. Thoughts and advice?