Is it wrong to let my boyfriend have with other girls?

im a very ually liberated person, im not a really jealous person, we've been together since we were children... recently he asked me if I would have a . I've been with girls before but not with him at the same time, it doesn't appeal to me, should i let him have with other girls? I mean he is human... I cant expect him to only want me right? right? uuummm help please!