Marquis turns 4

I can't believe my little boy is 4 years old already. Having kids really does make time go by super fast. We had a really fun birthday party for Marquis. He chose his them this year and he wanted Superman,batman and the hulk. So thats what he got. We decorated, i made him a cake and i made superman capes for all the kids. WE played games and ate and the kids swam and all the kids helped Marquis open his gifts. HE has been really excited about his birthday this year. He is growing up so fast. He is in the "goofy" little boy stage and its funny to see. But there have been some things going on lately that i don't know how to deal with. HE gets really angry and gets really mean and he gets really emotional. Not sure how to deal with it. He is also into asking me about things that i am not really sure how to explain, like "mom, where is your dad?" why don't you talk to him" etc. Not sure how to explain that to my now 4 yr old. I love him very much and can't believe he is already 4. He has been asking if he can have a brother to.
HAPPY BIRTHDAY TO MY LITTLE SUPERHERO!!!