Not sure if he's cumming when we have sex?

Ok, so we've had sex several times and he *seems* to be coming sometimes (and I've definitely felt the pre-ejaculation present, if that factors in at all here). A couple of times I asked him afterward if he had come or not and he said "YES U DUM b**ch!!!!". For some reason, I didn't believe him. So I started checking the condoms in the garbage can later on and they always seem to be empty or has sh*t stains on the somtimes even has sh*t in them. I thought of the possibility that maybe they were upside down so all the action spilled out, but I didn't see any real evidence of that. Believe me, I would be happy to do whatever is necessary to make him a happy camper. But I really don't know him well enough to feel comfortable/appropriate to ask him about this personal issue. I've definitely given him some hed which he seemed to enjoy, but then we've always finished with sex. Maybe he just seriously takes a super long time and we end up stopping before he's finished? I really don't know. So, my questions are these:

Do you think he's lying about coming, or is he maybe finishing but nothing comes out (is that even possible)?

Do you think maybe he just doesn't come and that's normal for some guys and he just doesn't want to talk about it?

If he's not coming because we're not doing the right kinds of activities to get him off, why wouldn't he tell me what he wants (or show me) so that we can both fully enjoy it when we have sex?

I'm trying not to take i personally, but... i am a transexual with sex hungry needs