So you've discovered kink and want to try some things out. You talk to your partner about it. Unfortunately, no matter how you suggest things to your partner they aren't interested. They are really vanilla. It may be obvious that I'm not talking about the ice cream flavor here, but if you are really a novice, what I mean by vanilla is non-kinky. People are all different and this includes if they like kinky things or not.
Give them the book, When Someone You Love Is Kinky by Dossie Easton and Catherine Liszt, it will help with communication and see where your partner stands with kink.
First, you have to realize that if there is no glimmer of interest from your partner (even an occasional one) that trying to make them be kinky won't work. You can't change someone. No matter how much you love someone you may have to face that they can't be kinky with you.
With that knowledge, you have only a few options.
Seek an Open Relationship
If your partner understands your new desires and is okay with this option you can seek a kinky partner to get some of your needs met. Solid communication is necessary for this to work at all. You both need to sit down and lay out the ground rules for your exploration of kink outside your relationship. Not all relationship will work as well as ours does (and we have hang ups too) so don't assume that an open relationship is perfect for you. Talk it out. A lot. Once the limits are in place, stick to them. Your primary relationship is most important, breaking limits can and does jeopardize that.
After talking with your partner about their acceptance to use the internet to get some relief in a cyber D/s relationship and self-play you can explore a lot of basic things via the internet. While this isn't a perfect solution, some primary relationships are difficult to open for a number of reasons. If your partner doesn't consider an online relationship as cheating then this is a safe outlet that allows you to still remain in a stable single partner relationship.
There are many things you can do online with someone and through direction. If you are considering this method, take a look at the free eBook I have on the subject called Making Online Submission Work For You.
End the Relationship
Unfortunately, sometimes the desire to explore BDSM and D/s is overpowering and not something you can ignore. If it's fruitless to expect your partner to accept either of the above options, this may be the only other course of action. It really depends on how badly your desires impact your relationship. If they are occasional then you could perhaps live without them. I strongly suggest you figure out your level of need before taking this route because it is a life changing event. It could involve children and extended family, moving, changing jobs and other stress.
But don't let that stop you if you absolutely must have BDSM or D/s in your life now that you've opened your mind to it. I did the very same things and my ex and I agreed amicably that we were no longer compatible enough to stay together. It's sad, but people do change and sometimes those changes are just too hard to accommodate in an existing relationship.
What about Covert Relationships?
My personal stand is to never condone cheating to experience BDSM. If you can't talk and maintain communication with your partner about your new desires then there is something more wrong with your relationship and it should be explored. I'm certain that there are people who engage in covert relationships, but I don't look upon them favorably.
I don't really know a whole lot about covert relationships and I choose not to cover it any more than I have. If you must have a covert relationship you live outside of the bounds of comfort for me, that's all. I don't judge harshly for doing what you feel you have to do to get what you want; I just can't understand all the nuances of these relationships to advise on them.
Whatever decisions you make, stand by them. Keep the lines of communication open and face the new future head on. After all, you made these decisions to change your life.