Anthony,,

Not unless you engage the thought, consenting to it.

If it comes and you quickly dismiss it, there is no sin. If you were to fully consent to it and engage it deliberately, realizing it was wrong and not caring, that would be a mortal sin.

I'd recommend you talk to your Confessor for further guidance on this. There are a lot of nuances and your Confessor is better equipped to help you discern in your situation your degree of culpability.

Eric Ewanco
It is good that you exist. You are worth more in the eyes of God than the entire cosmos..