Jesus really opened a can of worms with this one. Men (I’ve heard no women in this conversation) love to debate the definition and limits of lust, mostly in order to defend themselves.
I’ve heard some well-known teachers say that lust means you would if you could. I don’t buy that one. It cuts too much slack for our imaginations.
And truly this passage is about the imagination and our sexual desire. I suppose a passing attraction might possibly be innocent, but if that attraction is fondled and entertained, it becomes lust. I can’t tell you where the line to not cross is, but you know. Just as I know when I have crossed the line.
It’s all about keeping our marriage bond pure. If your wife knew what your were thinking, would she approve?
This is a pretty serious matter. It always has been, but with today’s easy access to visual stimulation, it’s a truly large problem. I suppose almost every married man needs to think about it and take steps to protect his marriage.