Should I feel bad?

My ex and I have been split up for about 3 months now. Due to him cheating, when I just had our first baby girl, She is now 5 months. He's still with the woman, due to something very crazy happening to her spouse. If I tell you guys everything, you guys would think this is a movie. Anyway, before the incident, my ex and I would still have sex, when I would take the baby to see him. Things have changed since, I pretty much distant myself from him, because all that was happening was me getting hurt. I wanted us to be a family, but seems like he doesn't want us back. Anyway, For mother's day he bought me a charm. For Father's Day, I got him a card, favorite ice cream, and little bit of weed. I didn't get him anything expensive for the fact that he doesn't try hard enough to see the baby. Pretty much comes when he feels like it, but he does a good job in supplying her with her necessities. So, the other day, when he went to see her, he had also invited me over to his mother's for dinner. When we were leaving he mentioned how he felt a certain way because I didn't get him a 'real present' and how I had someone else buying him shoes. Mind you, on Father's Day, he chose to spend the whole day with this woman, shopping. He didn't show up to see the baby until 8-8:30pm.... With that being said, Should I feel bad?? Should I have gotten him something expensive?