Its your skills and your lack of romance attention... and your pathetic way of couping wiht it man

If she was sexual before and it just stopped out of nowhere, there would be two things to look at. 1) Something is majorly stressing her and thus she's not getting in the mood. 2) You're not being romantic. Both of those are obvious so if she isn't majorly stressing (or at least more than normal/before) and you are being romantic to her, then the reality is, she's getting dicked by someone else.

She is too busy shagging other guys with bigger cocks. As she says..."you cum in your hand... they cum in my pussy"

welcome in married life :D