Sexy mature wants to be fucked

I live with my girlfriend, whom I'm also in a relationship with. We have a great time together, and things are going well in bed. We're both bisexual, and lately I've been thinking more and more about sex with a man. That I want to enjoy being with a man again. I've talked to her about it, and she's fine with it. She said, "I don't mind if you sleep with a man occasionally, as long as you don't leave me." And I don't, because I'm crazy about her, and I've suggested she join in if she wants to. She said she's still thinking about it, but I've already started looking for a man who just wants sex. The pleasures, not the burdens.