and the only meals out have been on me (his birthday)
At 4 months, he should still be at the stage of trying to impress you and win you over.....well he seems very confident of himself doesn't he? It's only downhill from here.
Also it’s me that seems to plan most stuff too as he doesn’t seem too bothered about doing that!
You're wasting your time.
He is lazy and low effort I'm afraid.
Either he's like that with everyone, or he's one of the MANY men out there who behave like this when they feel like they're 'settling' for a woman.
To compensate for the fact that they think they're settling, they make a deal with themselves which allows them to put their feet up. As long as they get to be in a comfortable, low-demand, cheap relationship where they're getting more of out of it than they're putting in, and they're getting fairly regular sex, they'll be quite content to coast along for years. That's why you feel like you're making the effort at this early stage.
There are also men who like to feel like they're the princess in a relationship, so he could be one of those too.
Search online for someone like LoveKateTaylor on Instagram. You don't have to agree with everything, but I think she's made some posts that I think you'd benefit from.