Does anyone else fall asleep whilst receiving oral pleasure

I am finally accepting that I am asexual but this really was triggered by falling asleep when in reciept of oral pleasure. I've always keen to get it over and done with so that I can get on with something I enjoy doing. Even housework is more of a pleasure! As a result of this, I'm not the worlds best person in relationships. I've never had sex whilst sober and have no interest in it. I can imagine it must be quite hurtful having someone fall asleep on you when there head is between your legs trying their best to throw you into raptures of ear slitting squeels of delight. Every relationship I've ever had has resulted in my making the other person feel so insecure that they then try and keep me locked in the house and away from other people. This quickly results in an end to that relationship and me having a stalker from any time ranging from a few months to the longest of all which is now in it's 12 year of painful unrequited love for that ex! I have tried relationships on many different levels. Male, Female, Transgender, polyamouous and just a regularish bonk buddy but nothing works! Though I am coming to terms with being asexual in a very sexual society I am curious to know if anyone else has experienced falling asleep during oral sex? This experience so far has been one that I have yet to find anyone else that has had the same happen. I don't just mean on an odd occasion such as if a bit drunk or totally shattered. This happened to me everytime! Is it normal?