My ex acts weird around my new baby

So I really don't expect anyone to hold my daughter if they don't want to but my son's father comes to pick up my son to my place and sees my daughter and he just stares at her and she stares him and as a baby she wants to go with anyone since she hasn't developed her stranger danger sense about people and she throws herself at him essentially but he just stares and I find weird that he stares and won't hold her but like I said I don't expect him to either