Why wouldn't they be equals? I don't know anything except what I've read about both of them, and just because they met in a bar and haven't stayed together forever doesn't mean to me that she's some goldigging harpy who got poor widdle star Hugh Grant trapped into parenthood. Just because she's not famous doesn't mean she's not his equal, and because he didn't use protection when having sex, he knew it was a possibility.I don't know why you even pretend that they are equals and that this is a 'normal' relationship.
Like I said, for all I know they dated, decided it didn't work out but were friends and both wanted kids at this point and so they decided to be co-parents. They would hardly be the first friends, or even the first exes, who had a kid together. Her ex-boyfriend's description of Grant coming over and them chatting comfortably at a restaurant while Tinglan was with her boyfriend and Grant was dining with another woman sounds to me that they're friends even though their own dating life didn't work out. Maybe the timing was right for both of them that they wanted a kid, maybe they liked that the other person understood not wanting to get married, or had the same perspective on life, or whatever, and so they decided to have a kid together. Hugh seems happy to be a dad and it sounds like Tinglan is being treated very well, so I don't know why anyone is supposed to feel sorry for him.