I think that for every sex act the emotionality involved is relative to the two partners. Every sexual act forges some kind of emotional connection, whether one, both or neither of partners are conscious of it. For example, in my younger days I had regular sessions of mutual masturbation with a close friend, not an uncommon occurrence, I'm sure. This forged a new level of closeness to our relationship (though having been practically brothers since the age of five, we were pretty close already) but it's never been consciously acknowledged or verbalized between us- it's just something we shared.

I do fall in love a little bit every time I am involved sexually with someone. I'm lucky that my heart is big enough to share with a great many people, and tough enough to understand that sometimes that person won't be in my life for more than an hour or so. I don't really have any practical advice on attaining the mindset that can handle that- it's just the product of my experiences.