Hey Kate,
First off I am going to repeat what everyone else has said about only you can make the final decision about your choice in this matter. I am a professional relationship/marriage counselor and one strategy I find helpful when working with clients is they tell you more during the introduction session then any other session. I get that this isn’t a session and if it were I am sure you would have much more to say so I could get to know you and your situations better. It is not my place to direct you in any specific way, but from what you have said so far I feel your words are very powerful, they are words you have chosen to write down and as you know they are reflecting your internal struggle. Ok, so now you are thinking “yes, I know this and you aren’t helping at all’, but I want you to take a step back and with that said I am going to repeat a few things that stood out to me as I read your posts:
“i've known my husband for five years
i'm 20
like the full lifestyle. i want a D/s relationship 24/7.
he told me flat out, it just wasnt something he was into
i understand you can't make someone like something.
the bdsm thing was definitely a BIG part of the reason for the seperation.
i still love my husband…but i also love this lifestyle. the more i learn, the more i desire.
i've found i can't stay away no matter what.
i'm going to have to approach the subject again with my husband”

After you have read the parts that stood out to me think about those parts I have quoted you from and what stands out most to you. Think about if there is something that you have previously said in your above posts that you think should have been included in the parts that stood out to me. Again, no one can tell you what to do and the parts that stood out to me may not be the parts that stood out to you, or that you wish stood out to you. But you made a very good point in saying you can’t make someone like something, and it goes both ways dealing with your struggle as in you can’t just put off you feelings and desires, which you seem to understand. Re-read that one line you wrote, “i understand you can't make someone like something” but think about it in reverse and referring to yourself. I could go on and on with this but I won’t, but if you wish to talk more in private I would be happy to do so. You are young and you have only begun to figure yourself out, and that goes for your husband as well. You don’t have any easy decisions to make, so I wish you the best of luck and remember only you know what can make you happy.