Sex with my boyfriend

Why do I feel like I’m constantly asking my boyfriend to sleep with me? It’s like, ever since I had our son he just doesn’t want too anymore. We weren’t together when I got pregnant. We where sleeping together on and off for years. Then I got pregnant and he was around but we still weren’t together. Then I had the baby, he decided to move in and “be together”. Okay great. And now that we’re together we don’t have sex? It’s so annoying. And if I bring it up he makes it seem like it’s not a big deal or he’s tired. Blah blah. IM tired too but I still wanna have sex lol how is it we had more sex before we where together and now, nothing. Ugh. Just had to rant.