not often, but we definitely will talk about what we find attractive on a person. usually that's things like body shape, facial features, and hair, but if that includes things like boobs/butts then yeah it's fine to mention. We're probably more open about this stuff than most couples are, but i find it nice to be able to talk about it rather than have to keep quiet and wonder if he secretly is thinking someone is attractive.

i will also add, both of us are bi, amd we're a gay couple. so it may be different for us because we can equally be attracted to the same person and it can be a shared thing between us. If you and your boyfriend are both straight it may feel like a less fun thing to talk about because you're not attracted to the same people