My husband and I don't break sex up into "foreplay" and "sex." If it feels good and we're touching or looking at each other, it's sex!
IMO, (I have got on this soap box before) the word "foreplay" minimizes the pleasure and beauty of anything other than PIV. In our relationship, penis in vagina sex is usually about 10-20% of our sex play. The rest is other stuff. And for us, PIV isn't the end all and be-all of sex. Also, sex may not end when he comes. Especially if I haven't come yet. Sex is over when we're both satisfied and cuddling, but we usually continue to touch and caress each other for a long time until we either fall asleep, if it's evening, or have to get up for the day.
The rest isn't "before" anything, and it's ALL play. Every action is just as important as any other. Seeing as the majority of women don't climax from PIV, I think the very word "foreplay" kind of denigrates women (and a lot of men) and the way they enjoy sex. But, that's just my opinion and many people use the word "foreplay" for everything that happens before intercourse.
Seeing as we often start PIV and then go back to oral or toy play or manual sex or everything else, the word "foreplay" simply doesn't make sense to me.
If we're touching each other in a sexual way, it's sex.
"Sex" usually starts by how we look at each other earlier in the day, the way I touch his hand during dinner, the way he caresses me while I'm cleaning up, the way he glances at my body while I'm just walking through the house or even just sitting down and starts long before we ever go to our bed.
Your mileage may vary.