Not a brag, really a disappointment, the first three women I was with all had a negative reaction due to my size. The first had a really hard time taking it at first but with enough foreplay was eventually able to let me penetrate her. A few times she complained about feeling a pain in her abdomen, I have always assumed I was at her cervix.
The second woman I was with, I was barely with. She wanted to have sex and before the head of my cock was in she started crying. I stopped immediately and she buried her head in a pillow and just wouldn't stop until I told her I was going to leave and she asked me to stay. We never really had sex, just that first attempt at penetration and one more after that ended similarly. I felt awful about it, and it actually turned me off to sex for awhile.
The third had more experience and was noticeably looser than the other two. She had no problems when she was riding me, but when I was on top she said the same thing as the first, though, she wasn't really opposed to it. Instead of complaining about the pain she said "Fuck, that's so deep."
The first two made me feel bad. I really liked both of them a lot and just wanted to please them, which felt impossible at the time. The third is a mystery to me, it was the result of a drunken hookup. I don't feel good or bad about that, I feel nothing. For the the first one, I feel like my experience led to me going in deeper than she was ready for.
I don't think there are really any guys out there that have a penis that is too big for a woman to take, aside from people with deformities. I do think that it is possible to be too large to meet someones sexual interest, not everyone is into huge dicks. When reading through other posts in this thread I felt like more of the experiences were the result of the partner just not wanting something that exceeded the size they see as ideal, or that far away from their ideal.
I hope my descriptions were not taken as boasting. I honestly still feel bad about the first two I mentioned and the experiences had significant impacts on my willingness to have sex with others so readily.