Wow.. Okay.. That makes sense.. Thank you!!
I assume he's feeling the orgasm but not the ejaculation. This is common as the main feeling of ejaculation is the wetness and temperature change when it hits the skin. The penile spasms that cause ejaculation can often get lost in the overfall sensations of his orgasm. If there is a large amount of vaginal lubrication you sometimes can't feel the ejaculate when it happens inside the vagina. If he ejaculates normally with manual or oral stimulation than most likely he's also ejaculating during vaginal sex, he just can't feel it as much.