My boyfriend just changed suddenly – lady laments

My boyfriend just changed suddenly - lady laments
From a female blog reader:

Okay, so I’ve been dating my be for 9months, everything has been perfect but for 2-3months my bf has changed, he doesn’t converse & have laughs with me anymore, he just seem so serious & hardly smile.

He doesn’t even talk to me I do all the talking & he will just give me 1 word answers, he gets irritated & it seems like I’m doing something wrong? I’m a good girl, I listen to him & do whatever a good gf does but I don’t think he’s happy with me. I’ve told him he’s been acting weird lately & should talk if there’s anything wrong but he says he’s fine he’s just tired from work. He’s just changed, he’s so serious & he has this look on his face just saw him, haven’t seen him in a month & he doesn’t even hug or kiss me, just look so serious.

Is he not happy with me? We were making plans on getting married but I said we should stop as soon as he started this serious quiet behaviour. Has he just lost interest? I don’t know what to do. He doesn’t even smile anymore or talk to me:( what should I do? I’m so confused:( my mum likes him & says he’s a good guy but I don’t feel like he’s happy with me. We’d be driving for 30mins & he won’t say a word to me:(