ADVICE: I’m ready for my kid to meet my BFs kids

I’ve been dating my BF since abt January he got divorced in October of last year... now the holidays are coming up & im not trying to waste my time but our kids haven’t met yet & I feel like they should meet & get to kno eh other etc if we are making plans to be long term... he tells me their mother doesn’t them around anyone he is dating but yet she brings them around guys she dates... off the strength of this alone I’m ready to let go of the relationship... I’m just I guess kinda stuck b/c we click perfectly but if my kid doesn’t get along with his 2 then my time is & will have been wasted... I need some advice on how to go about telling him this without coming off like I’m trying to start problems with his ex