Do you think it’s appropriate for a partner to get turned on by one of their other partners and then ask a different partner for sex? Especially when they know that their partner was turned on by someone else?

This is the kind of thing that really differs between people and relationships - there is no all-encompassing statement anyone can make about whether it’s “appropriate” in general. If it works for your relationship, it works. If it doesn’t, don’t do it.

If it makes either person uncomfortable, then it’s probably not healthy or appropriate. If everyone involved is okay with it, then it’s not a problem.

Sometimes, you just can’t control these things. Say you’re in a long distance relationship with someone, and have another partner you live close to. If you’re sexting with your long distance partner, and then you’re really turned on and take that sexual energy to bed with your other partner, that seems fine to me. If you go on a date with Bawb, and he can’t take you home at the end of the night because he has an early morning meeting, but you were really gearing up toward a sexy evening, so you meet up with another partner for sex, that seems fine to me. 

Of course, if your other partner is uncomfortable with that, drop the issue. Don’t be insensitive and say things like “Matchew got me really turned on, and now I want to have sex with him, but he’s in another state so you’ll have to do.” Don’t be obvious or obnoxious about it.

Don’t use someone to get you revved up for someone else’s benefit. If Garthus puts all the effort into a romantic date, but you package that well-stroked libido up at the end and deliver it to someone else, that’s not cool.

Ultimately, this is something to work out with your partners. What are they comfortable with? How do they feel? That is way more important than whether an internet advice blogger thinks something is or isn’t okay.