NEED ADVICE! TO FUCK OR NOT TO FUCK

ok so my bf and I are in a serious relationship but it's taken us a while to get to where we are. I love him but he knows I've always been curious about girls and since the beginning he's always told me he's wanted to experience sex more with others and just have fun (we lost our virginity to each other). at first I was kind of okay with it because I wanted to explore with a girl and I settled for doing a threesome but now he wants to do more than a threesome. here's been talking about this for three years. I know for a fact he's never acted on it but I feel like we can't move on until he resolved that. I agreed to have an open relationship with him because I know he'll keep bothering about it and I don't want to be married with kids and he still feels that way. we're in our early twenties so it seems fair to let him explore as long as he's careful obviously. the point is we agreed that if he's gonna fuck around I can too. I want to wait until he does it first before I fuck someone else but there's this guy who's been trying to butter me up for the past few days now and I think he's kinda cute. I don't know what I should do. I need advice but please don't judge me too harshly