Taurus man acting cold. What do I do—?

Oops. My bad yal. I guess I put this in the wrong place.....I'm a taurus female and I thought dealing with another taurus(male) would be easy but I'm facing a

challenge. I've been dating him for 6 months and we get along great. We hang out all weekend and talk everyday. Hes also 4 years younger. I'm 25 and hes 21. I didn't want to deal with him at first because of his age and hes in the military, but he's so sweet and loving (when hes not acting cold). so we eventually started dating. Also him being in the marines gives some maturity. All my friends love him and he even hangs out with some of my guy friends one on one. Hes really intergrated into my life and I've grown to trust him which is a hard thing for me. I haven't introduced him to my parents yet, because my parents think everyone they meet I'm going to marry and when he acts cold torwards me it doesn't make me feel secure in the relationship. Also with him just being stationed here I sometimes get a worry feeling like we wont last, even though I want us too. Then he talks about the future with me and it changes my whole mindset. He would talk about getting married, having children with me etc. What caused our rift is because I asked him for better communication last week. I told him I feel like sometimes we aren't on the same page and it makes me uncomfortable. For example when we argue he completely shuts down and shuts me out. Once I brought this up he shut down. I was trying to advoid that response so I didn't approach it in a harsh way but apparently it came off that way to him. He also said I was moody all day to him. Thats also another thing that I cant stand is that I feel I have to walk on eggshells and have to always keep up a happy persona because God forbid I get mad, moody or indifferent and he shuts down. He can be moody 24/7 and I dont say a thing. Ill be like "babe whats wrong" and he'll say "baby chill I'm in my zone I dont feel like talking". But if I were to do something like that we would become distant. Since last week hes barely talked to me. I texted him earlier telling him i missed him and he responded saying " I miss you too babe". I told him he means a lot to me and all I got back was a same to you. I dont understand how me asking for better communication can cause a ripple effect of us having no communication. He told me he understands my viewpoints and where im coming from, but then he turns around and goes cold. Hes stopped being affectionate and lovey dovey as well. Hes become very dry. It seems like he thinks im changing him and thats not the case. I just want communication. What can I do to fix this because right now I'm in a pit of despair.

While I agree with the above you also have to recognise the difference in your maturity. You're a 25 year old woman and he's a 21 year old kid.

Being a kid, he's going to behave like one. Expect periods of petulance and selfishness. Being a marine won't make his brain grow any faster. He's still neurologically speaking, still growing.