After seeing the memory of James bullying Snape in the Pensieve, he wonders if James forced Lily into marrying him once or twice.
Second, it makes Lily look like a stupid, weak little girl who couldn't defend or take care of herself and couldn't let herself be happy, which is totally contrary to everything Rowling has ever told us about Lily.
There's Lupin's staunch refusal at first to accept Nymphadora Tonks' affections for him because she possibly couldn't handle him during the full moon (despite being an Auror). Sirius Black and Remus Lupin are homosexual lovers.There are plenty of romantic and sexual subtext in Sirius' and Remus' relationship in the books to make it possible.