Weird fantasies?

My boyfriend and I have been together for a year and he recently told me he has a desire for me to be double teamed (me being pounded by a guy with a bigger dick than him and himself getting head from me). We are very open and communicate well while being honest and I expressed me being uncomfortable having another guy there seeming I haven’t had the best experiences with men being respectful of my boundaries and wants. I like the idea but I’m really afraid of another guy there seeming we don’t have another man in mind nor do we know one that would be into that. I’m really scared of another man being there but I’m willing to try a dildo to see if that’s even something I’d enjoy before I try it with a guy but idk if that’s weird. The dildo would be used for head (my boyfriend likes the idea of hearing me slurp on cock while he hits from behind and me moaning from being fucked while he gets head) and vaginally. I guess I’m wondering if anyone on here has had a similar scenario or positive advice. Thank you in advance and if you have any suggestions on super affordable dildos (preferably 7-10 in) that would be much appreciated thank you 😊