Remember that searching for a new partner, while your with a partner, takes time away from the relationship.
Exploring your submissiveness with your current partner may be very exciting for both of you.
If you decide to seek an online dom, then there is some great advice already posted.
There is a difference between an online relationship where you may act out your fantasies in e-mail or chat, versus acting out your fantasies in real life with another person. Your limits may not be the same. If you are going to fill out a limits checklist, feel free to use the one in my signature. It has the same basic set of questions found anywhere, but was modified specifically for online relatonships.
http://www.vampirespet.com/ActivityChecklist.html
An RTF version can be downloaded here:
http://www.vampirespet.com/ActivityChecklistInRTF.rtf
And, you may want your partner to fill out the questions on his own.
It will provide you both with lots to talk about and you can see how compatible you are on many things.
Be safe and good luck!