Not being able to cum

Tay

When I’m on the phone with my boyfriend, and we’re talking dirty, and I start to masturbate. It feels good for like a couple seconds but than stops.... and I just can’t orgasm, even tho he makes me turned on.... and I don’t want him to get upset, thinking he can’t make me, so I fake it. I read things on this and they say “some woman just don’t cum” but I really want to and I’m scared to do anything with him because I’m afraid I won’t orgasm and he’ll notice.... what should I do?