Has anyone ever bled from having sex?

Last night me and my boyfriend were having sex, done this a number of times funnily enough but last night there was blood on the condom we'd used.

I'd already my period last week and mine are always on time so I knew it wasn't that and I went and checked anyway and it disappeared straight away.

Has anyone else had this happen? I'm just wondering if something was torn slightly which caused a small amount of blood or at least some form of explanation.