I don't mind Ollie, Dick and Roy being playas. It feels organic to their characters. I would object if it was Hal, Barry, Clark or Ray Palmer being pushed into those roles.
In Dick's case, I think it's due to a combination of his long published history with all the love interests he accumulated over the years ended up getting consolidated by making him a playboy and there is also the large female fanbase who lusts after him. Ollie being an actual playboy as opposed to Bruce pretending to be one, differentiates him from the latter, imo. I don't think he should be a cheater though, maybe he did it in his pre-island days before he got humbled, but I think he should be committed (or at the very least trying very hard to) in the present day. Roy, being Ollie's prodigy probably picked up a few of his mentors habits.
I see Ollie and Roy as people who are actively, unsubtlety trying to get laid while Dick is more of a natural charmer. He's not trying to get laid but he's nice, caring, athletic, good looking which ends up making him a good catch for the ladies. An Accidental Player. If he is dating, he will be 100% committed to his partner and to his partner only. I think him sleeping around can be explained away as thus; he won't do it unless he thinks it's going to lead to something deeper and more meaningful but he is also a bit too trusting for his own good and his desire to be more emotive and connect with people better than Bruce did sometimes leads him to bed with people he maybe shouldn't be with like Post Crisis Helena Bertinelli.