FaceTime sex!

So my boyfriend and I are in a long distance relationship (military relationship) so I'm only able to actually talk to him until the weekends. We sometimes have sex seshes on FaceTime like masturbating and stuff. And I'm confterable with it. But lately he constantly keeps asking me and I always say no. I don't know why I never want to do it anymore? Like we are both very sexual people and I'm confterble doing I just never want to and he always pressures me constantly when I say no. But I don't know if it's just him asking me so much cause he misses our physical relationship. Do you guys think I'm dumb for sayin no and any reason why I don't want to? I don't know why I don't want to I just feel like such a bad girlfriend in this relationship.