First off, welcome to the forum :-) I hope you'll get some replies to your message that help you figure things out a bit more.

Secondly, here's my ten cents for what it's worth. You have finally found someone (not just someone, but your husband!) who is willing to explore this with you and there is absolutely no rush to jump in at the deep end so just take your time and do things step by step. Taking it slow is key in my opinion, if you want to make sure you do things at the right pace for each other and so as not to do something that pushes your limits too much before you've properly figured out what they are.

As your willing partner in crime, I think you'll be pushed to "scare off" your husband if you do take things slowly, but I would really, really just reccommend talking more together about what you would like to try instead of just going for it without any prior discussion. Even something you think you might like could turn out to not bring out the desired effects in you, so always be aware of your reactions to what you try out, and try to stick to what you've talked about trying - don't spring anything new on each other in the heat of the moment unless you exchange a few words there and then to make sure it is what both of you want.

You said in your post that you're very open with each other with regards to your wants and needs, and that's great and you really need to keep that up and keep those discussions at the heart of your BDSM activities. Read each other's reactions when you're playing, and maybe it wouldn't be a bad idea to start off with you domming him more in a mental and emotional way than physical, since you seem to be very into causing pain and this might come as quite a surprise if he's not already used to that. Of course do things slowly here too, so his body can build it's way up to taking any more sadistic plans you might have! Remember there's no rush, you have forever to figure out what you like so do it bit by bit.

I may have been repeating myself a lot here but I think that just highlights how important I think a few key factors are. Nobody (correct me if I'm wrong!) comes into BDSM knowing exactly what they like, it's a trial and error situation for everyone, because as you said just because you like the idea of something in theory doesn't necessarily mean you'll like it in practice. You probably will make 'errors', by which I mean you'll try stuff that one or both of you don't enjoy, but that doesn't have to mean you've 'done' it wrong and should stop exploring more. Just be aware of each other and talk, talk, talk about it - before, after, and even during if it doesn't ruin the mood! Together you'll find your limits so work together and keep that openness you have already.

You and your husband have more answers between the two of you than I'm sure anybody could give you on here, but internalise what people suggest to you and figure out if you think their suggestions could work for you. Good luck!