I'm on the other side of the situation. One of my closest friends is male and I am female and we have dated each other. That was a long time ago, and we realized that we made much better friends than lovers. So, when I start new relationships I make my new partner knows that I am friends with one of my exes, it didn't work out, we never had sex, and it isn't going to work out. We're just friends. I've never had any issues with it. As for guidelines, just talk it out with your partner. Talk about what you are comfortable with and not comfortable with. Some of my boyfriends have asked for me not to be alone with my friend and I was ok with that. We would hang out with a group or hang out in public. Others trusted me completely and were even friends with him too! Its all about what works for you, but it can definitely work out.
Generally, I don't really have a rule when it comes to friends, if the line is crossed then I have an issue. Some people truly won't have respect for your relationship, and will cross the line- those are the people that can be cut out. I'm currently dating someone who has some of the opposite sex friends, i have no problem with it, because they have all been friends for a while and I think what eases my mind the most is that the female friends of my boyfriend, are in committed relationships, but i have been in the situation where I had to tell my boyfriend not to talk to some people, simply because they were being disrespectful, and he acknowledged it, you just have to talk it out and think rationally, rather than having a huge argument.
I am very territorial over my husband. But I do not like him having opposite sex friends at all because, I don't trust them and there's a small part of me that does not trust him as well. Reason why is because while I was visiting my grandparents for a week with little to no cell phone service and on the mountain, he snuck off and met his ex at Walmart as friends because they both "needed someone to talk to". He claims they didn't do anything. And I believe him. But it hurt me very bad. It brought my depression back and gave me anxiety. He was planning on keeping it from me but I found the messages between him and her on Skype saying that they would meet in the pharmacy section and he gave her his number encase of emergency. Needless to say, I sent her a message on Facebook with a fake account saying it was me (she blocked my real account), and I blocked her from his Skype and Facebook. From then on out he isn't allowed female friends and I don't have male friends and tend to steer clear of them.
I don't believe it's fair to attempt to dictate your partners friendships. I was in a relationship with a man who tried to tell me I couldn't have any male friends, and all it did was push us further apart. I feel that by telling someone they can't be friends with someone, you're telling them you don't trust them. And without trust a relationship will fall apart. If you're very uncomfortable with it, try explaining your reservations to your partner in a non-accusatory way, and attempt to lay out some ground rules for friendships. The ones that Ed mentioned are very practical ones, but of course each relationship is going to be different.