You did not state the age of your boyfriend, so it is not clear. Let me, however, provide you with another law: Murphy's Law: What CAN go wrong, will go wrong. So, consider if you want those sentiments and pictures sent out to your contact list,or his, or who knows.
If he is also 21 or more, not linked by (say) being your teacher, you are probably OK. BUT, please spend a few minutes reviewing all the "Internet" category answers to see all the tales of woe, betrayal, hacking, and just errors.
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, I accept a retainer, and we explictly agree to enter into representation.
It's not illegal if you're both adults, but it's not wise. To add to my colleague's good advice, I'll mention that just because you're consenting now, and he's your boyfriend now, doesn't mean that will always be true, and you really need to think about the future. You're going to be applying for jobs and school and whatever --do you really want nude pictures of yourself in anyone else's possession and out of your control? Once something's posted on the internet, it's virtually impossible to get rid of it. If you want to keep the bf interested, find another way that doesn't put your future privacy interests at risk.
Avvo doesn't pay us for these responses, and I'm not your lawyer just because I answer this question or respond to any follow-up comments. If you want to hire me, please contact me. Otherwise, please don't expect a further response. We need an actual written agreement to form an attorney-client relationship. I'm only licensed in CA and you shouldn't rely on this answer, since each state has different laws, each situation is fact specific, and it's impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.