People's assessments of the Ryan Reynolds character are so colored by puritanical moralizing
I don't believe sexual monogamy is a natural state for human beings (and my wife knows this by the way), so I don't judge him for being a womanizer. If I had his looks, I'd be womanizing like crazy too (and even as a more moderately good looking dude I have had my share).
But clearly many people don't agree with me about sexual morality, and I'm probably not going to change your mind if that's the case. I would just invite you though to look at his character and see if there's really anything else about him that suggests he's a jerk or a sleazeball. Isn't he actually pretty nice to everyone? Pretend for a moment you don't have a problem with adultery and womanizing. Is there anything else he does that is mean-spirited?
Keep in mind that Ryan Reynolds's infidelity is not a crime, whereas Jesse Eisenberg engages in--okay, the victimless crime of marijuana possession which I don't really count, but also repeatedly drives drunk. Which I do count, because that jeopardizes innocent people's lives. Yet so many people who judge the Reynolds character seem to give Eisenberg a pass on this. 🧐