lilsweetie, first welcome to the forum.
The concerns that you have are very typical of those that are facing polyamory for the first time by having a partner that would like it. there are plenty of folks around here that have been through these experiences.
however, you have posted this in the "Dating and Friendships" section, which is usually for folks looking for others, and not really to get into a discussion or ask questions - maybe you could ask your question in an introductory thread in the Introductions area - I think you will get more answers there.
Hope this helps!
"Listen, or your tongue will make you deaf." - Native American Proverb