Is there an alternative to using condoms that prevents against stds?

Can someone tell me about female condoms, like how/where I can get them like if I need to get them thru my doc/pharmacy and how much they cause and that sort of thing? Do you notice them yourselves when you use them or is it not as pleasureable?

Is there something wrong with having changing partners often, as I have not found my one and only as of yet and sometimes just need to feel pleasure as does the man?

Thanks in advance for your help and suggestions