“Hello I am 16 years old and pregnant. My boyfriend is 26. However I lied to him and told him I was 18. Then I got pregnant and told him I was only 16. Can he still go to jail because I lied to him. Even if he just wants to help support his child?”
Yes. In many states an adult can go to jail for statutory rape (which means having sex with someone who is either underage or who has some condition which renders them unable to give aware, informed consent) even if the person agreed to it, or lied about their age.
However, in order for that to be the case, the government has to be willing and prepared to prosecute, and *that* can vary from state-to-state, and indeed county to county. Your best bet, in this case, is for your boyfriend to consult with an attorney who does both criminal and family law, and see what they recommend.