I saw my mom having sex with my boyfriend

What should I tell my mom if I saw her her having sex? But with not her own man, with mine!
Last night I was in my room and I heard 'OH YEAH BABY'!' So I went into my mom's room for a peek because I thought she was watching the basketball game (she said she was) But I saw my own boyfriend on top of my mom naked. He told me he was too busy. From all my evidence, My boyfriend sneaked from my mom's window (the clang I heard), My mom lied to me. And they were doing it with each other. I know it was my boyfriend.

o thts gotta suk..I feel reely bad

thanks.

Wow...well I think you should tell her how you feel and I think that you should break up with your boyfriend. They both lied to you and you didn't deserve what they did. I feel really bad for you... you deserve WAY better than that. If I were you I'd tell them off!

Yeah. I should say somthing. Thank you!

oh my god!! ummm...
you can go talk to her while she's making breakfast!!
or...
when she's calm! and if you usually talk, and you know, you always share your secrets and feelings with her, you can ask her while you're talking with her in general! (as if it's something you want to know about)
and before you ask her, tell her: 'MOM' (take a deep breath) 'DON'T LIE TO ME PLEASE' (another deep breath) 'I SAW WHAT YOU DID THAT NIGHT'
or...
if I was in your situation, I'd ask my boyfriend first, and I'd tell him not to lie to me if he truly loves me! and you can also tell your boyfriend that you saw what he did with your mom !! he's feel shy and tell you the truth if he truly loves you!! if doesn't care about you, he'd never tell you what he did!!! (I'm so mad at HIM) how could he accept that ?!!! I mean... he has YOU (DUH)!! why would he do that with his girlfriend's MOTHER!??!!

oh wow.
um...first of all
DUMP HIME!
second
um...do what ann_13 says
about talking to your mom
but when you do talk to her, don't go with an agression, cause
thats not going to get you anywhere

THANK YOU ALL!

wowww, that's deffinantely not right, I feel really bad too.
Yesss dump him!Lol if that happened with me id probably use that against her when she won't let me do something..but wow.
I absolutely agree with ann_13.

ewww thats just gross any way just tell your mom and your boyfriend that you know bout that thing that happened.

I hope you are noy with him anymore and what did your mom say?