Communication communication communication is the first expectation to tackle. You've said your talking, and thats fantastic. Maintain it! That is one of the single most difficult things to accomplish for those couples who live together. Both in and out of the lifestyle.

What are the hard limitations for each of you would be the first thing to spring board as you put it, then talk about things you aren't against, but nervous or afraid to do.

Google BDSM checklist, and fill it out separately, then together. Talk about what you put down.

Then talk about what dynamics you want in a relationship. You can Google BDSM contracts, but understand they are not a legal binding document. They are more of an agreement from both sides on what you expect from the other.