Probably not. I know I wouldn't like the idea of my girlfriend making out with another guy so it wouldn't be fair for me to make out with another girl. I wouldn't become an actor in the first place nor would I pursue a serious relationship with a girl who is an actress.
Also this may be an unpopular opinion but I do think the nature of their job plays a role how often their marriages/relationships fail. They are constantly traveling and spending large amount of time away from their SO while trying to build a connection and emulate passion with their attractive costars. I think it makes it very easy to develop feelings for other people and cheat on your spouse.
I would rather not. Intimacy is not something I am comfortable with, so I'd stick with only being intimate with those I was close to. I always wonder how people can play a role, and stick their tongue down a co-workers throat, like it is nothing, with 200 people on set filming everything, caterers walking around, and back in that corner, your wife and her husband looking on and having a chat. no, that's all fucked up. these people give us great entertainment, but there is a reason why their marriages fall apart.
absolutely. it's just part of the artform. it probably means kissing people you aren't necessarily attracted to. it probably means kissing people regardless of if you are in a relationship... but i'd definitely do it. it's just a job