What Causes Ejaculation After Bowel Movements?

I'm 49 yrs of age. Over the last couple of months, after completing bowel movement, I start getting this urge to urinate but instead of urine, semen comes out. Not a constant flow but still a rather large amount. Followed by a small amount of urine. I get up and still feel this need to urinate so I wait another couple of minutes and a bit more semen comes out. This doesn't happen every time I have BM but it happens at least 3-4 times per week.

FYI, I have no type of burning or itching when urinating but I do have some small amount of discomfort after the semen is discharged. This also happens after ejaculating during intercourse.

So, I'm just concerned about the whole thing.