My boyfriend has Baby fever

I am 22 dating a 18 year old soldier..it's only been a couple of months of us being together almost 5. We don't use protection and usually he pulls out..but lately my boyfriend has crazy baby fever and almost every time we have sex he cums inside me..I can almost gauruntee I'm either already pregnant or going to be soon..it doesn't bother me because I wouldn't mind having a baby but I've never told him that I actually tell him we don't need babies now even tho we both are finacially stable it's just he's so young I wonder if he really thinks it through..we plan to get married soon but I didn't want pregnancy to be a factor. What do u guys think???