Can Semen Get Stuck In The Back Of Your Throat?

Can semen get stuck in the back of your throat? And if so how do you get rid off it I have been coughing up what looks and smells like seamen for some time now and it won't stop no matter how much I cough up it always comes back again although I don't intentialy swallow any I am a male and I am worried about my girlfriends loyalty as some times her breathe smells like penis I don't perform oral sex on her however because I don't have full trust in her, she has told me strongly that I am paranoid and that its a mental thing in my head. although when I kiss her I believe it's getting stuck in my throat constantly from the residue of her previous hidden sexual experience she had before she met me ect I am a smoker and know what mucus looks and tastes like and this is not the same it is sticky and clear and white and just looks like seamen not like regular saliva with bubbles ect and it is at times very sticky or/and stringy sometimes I wake up at night struggling to breathe for a few seconds and I struggle to sleep from the feeling of this stuff in my throat it's never ending I need to get help but I'm to scared of what people think about me I need to know if it's seamen I'm coughing up or just a strange semen twin form of mucus or saliva?, if I have proof I know I will be able to move on with my life and keep down a job ect I seriously need to know.
It never has any other colour just like how mucus can be yellow ect this substance that I'm coughing up is white/clear constantly and it is sticky and stringy tastes like seamen and smells like seamen and the taste creeps into my mouth some days it won't be there almost none then it could be there for 3 weeks straight it's really frustrating and embarrassing but if it isn't semen although I'm almost certain it is could you please help me identify the problem and also to resolve it thank you very much.