In A Bind, Keep Baby From Him?

My ex and I have been separated for 3 months now, we share our now 5 month old baby. He hardly calls to check on her, Maybe every 2 or 3 times out of the week. He works Monday-Saturday, but will come see her 1-2 days out of the week for a few hours. His excuse is that he works, yet he prefers to spend time with his new girlfriend. He doesn't offer if he can watch her overnight, and I've already told him he needs to step it up, as far as seeing her. Which to me, doesn't seem like he's improved. With that being said, should I just tell him to not even worry about coming to see the baby at all? Especially today, being fathers day and all.