I had sex with my bestfriend!

I had sex with my bestfriend and we are both straight.
We were both very drunk and she was staying over and I was having trouble undoing my dress zipper, it was stuck and it was in the back and I couldn't get it so she helped me. And than she got undressed aswell (we've been best friends since we were 8 we never cared if we saw each other naked). Now we didn't go get changed into something else because we both have always found it much more freeing and comfy to just be naked when possible (is that normal?) so I'm pretty much always naked at home except when we have company. So we went down stairs got a snack and started watching a movie together. And than she ended up spilling pop on me by accident and she was wiping it up than she started using her mouth instead, I tried to push her off a few times but she wouldn't get off me. She kept sucking and sucking I told her to stop a few times she wouldn't stop and than she started sucking my vigina and after a little while I started to actually enjoy myself and like it and joined in myself. And I've been really wanting to do it again! And it's only been 3 days sinces it happened!
She said to me she's been thinking she might be bi for a long time and she's been attracted to me for a year now. I've never felt that way about her, or about any girl I never thought of anyone other than guys in a sexual way! But now I can't stop thinking about that night... and I have a husband and she has a boyfriend! How are you supposed to tell them something like that!?!?
So is it normal??