Bluntness causing issues in relationship

I’m hoping someone can offer some advice.

I am 22 and have been with my boyfriend for 2 years. I was diagnosed with autism several years ago but am still coming to terms with what the diagnosis means to me.

my boyfriend is neurotypical and I feel like he doesn’t understand my way of thinking. Recently my bluntness has put a lot of strain on the relationship as I will say things that hurts his feelings without intending to. For example, he mentioned that since stopping going to the gym he doesn’t have a six pack and I mentioned that he doesn’t. It’s things like this that make him feel hurt which I understand but don’t know how to stop this as I often say things without a filter.

He mentions that these comments are putting him down and I want to change but I struggle as I don’t realise I’m doing it and am unsure how to change.

Has anyone struggled with something similar or have any advice?