It's only a problem if you forget to start breathing again.
I stop breathing during sex. I'm really sensitive and when I get to the point where I'm about to scream I just stop breathing. Is this a problem?
Your partner probably appreciates it. Next to uncontrolled laughter, there's nothing more likely to throw a man off his game than an unexpected scream so close to his ear. >:-/
I had a partner like that once ... And she would faint when she had an "O". Scared the shyte outta me, the first time. Was a real turnoff for later intimate moments, 'cause she would faint before I "finished" - and I wasn't gonna keep going while she was unconscious - so it kinda ended our intimate relationship. (we stayed friends - without benefits).
thats perfectly normal