Threesomes, should I or shouldn't I?

I am currently sexually active with my boyfriend (lets say his name is jake). were very much in love, but im looking to explore. a threesome is one experience i would like to have just to experience it to know what its like. my ex-girlfriend. (her name will be jenna) is also intrested, they both are intrested in having sex with me, just not with each other. however before jake an i started going out jake was intrested in jenna and vice versa, how do you think i make this work on all three sides? please give opinions and advice. =)