secret sex at college

i got married last year but still go out to parties sometimes, you know? met this chick last night, real hot and funny. we hooked up in an empty classroom. her tits were perfect, big round things that i squeezed while she rode me. then we did it standing against a wall, her wet pussy sliding up and down my hard cock. now im wondering if its normal to do stuff like this when youre married? anyone else ever cheat or fuck around even though they love their spouse?