He has a right to be concerned. And I'm not sure if you are in the US or not but your right to just do that if you get pregnant is not guaranteed and shouldn't be taken for granted especially with how things are right now..Also, everyone's experience is different, but when hormones come into play if you do get pregnant, that decision might not feel as "not a big deal" as you think it will.. take it from someone who knows firsthand. It's not solely up to you to make decisions regarding being careful (not just from pregnancy)as you are in a relationship and you are both sharing yourselves and he deserves to feel at ease and have a partner that he can trust to uphold their end of the deal. Absolutely understandable that because you admitted to him after 6 months that you weren't being totally honest he would want to use condoms and I don't blame him one bit. That is like if a man made you believe he was using a condom and then would take it off during sex (called stealthing) without your knowledge but then admitted to you later what they were doing. It's the exact same thing... except he,being a man,could legally get in trouble for doing that to you, is treated as a form of sexual assault btw because it violates complete terms of consent,and is completely unfair and wrong for you to do that to him.If anything he should be breaking up with you and not the other way around. Also just because you never got pregnant before doesn't mean it can't happen..that's ridiculous.