If you are getting a white discharge from your urethra, it could be an overabundance of white blood cells in your urine. I have a naturally high white blood cell count, which some people do. Others when they have a high white blood cell count will get a milky white discharge and will have UTI symptoms along with it.
Semen does not come from the urethra. There are two separate routes for semen and urine. The urine route shuts off when a cis guy ejaculates.
If you think it is coming from the Urethra then it could be UTI, yeast infection, Chlamydia or it could also be a sign of diabetes. One of the signs of high blood sugar is yeast infections (and yeast infections do not have to be in the bonus hole). If you are obese and take T, unexplained yeast infections can be one of the first signs of diabetes. This was a wake up call to my partner who is on T and now has type two diabetes.
If you are intersexed, then maybe there is something else going on entirely, but since you are saying it is coming from the urethra not the glans, then I would definitely say consult a doctor.
There are several things which men are prone to which trans guys are more prone to like diabetes, high blood pressure, etc.
However, instead of asking for medical advice here, perhaps you should be consulting your primary care physician who knows your history. It's can be dangerous to ask for medical advice from people on the internet. Peer support and help with advocacy is great, but most people on the internet are not qualified to give you medical advice. Any doctor qualified to treat trans* people will also be able to answer your questions about ejaculate as well.
And from the biologically female viewpoint, I experienced "female ejaculation" prior to transitioning hormonally. The discharge I experienced did not come from my urethra. It gushed in a very high volume out of the bonus hole area. When you have that kind of orgasm, it feels like a really highly intense pressure building up. (I'm not sure how much detail is cool in this forum so I'm trying to keep it clinical)