not when i was real young no but in jr. high and highschool my mom was engaged and her fiance lived with us, and well yeah i never saw anything but i heard it. luckily i had a radio beside the bed so i turned it on really loud and from then on developed a habit of sleeping with the radio on at all times until i moved out.
after they split up also, i was in the grocery store with my mom and she ran into a friend who asked about the breakup and somehow sex was indirectly mentioned and she said "it wasn't that good anyways" guh.. so.. didn't... need... to know... granted i was like 16 or so but i was still shocked she mentioned that in front of me.
err also once i heard my brother. *shudder* way more disturbing. my mom was away and his girlfriend was visiting from out of town, my mom convinced them to stay in her room while she was gone because his room was in the basement where the laundry etc was and my mom knew i'd have to go down there at some point, plus he had a single bed so they'd just be uncomfortable. well her first day there i had about 6 or 7 friends from school over, we were watching movies in the middle of the afternoon, my bro and his girlfriend snuck upstairs, and lucky me my mom's room is directly above the livingroom, within seconds i could hear the bed and floorboards creaking. oh god
only one of the other girls noticed, she looked at me kinda confused and then realized what it was and looked really grossed out. i just turned the movie up really loud and hoped nobody else would hear. eck.
also any time i went downstairs to do laundry there were always condom wrappers on his dresser in full view
my mom saw them once and just said "well at least he's using them" bleh.