Is there something wrong with me 😖

I think my boyfriend (of 2 years) is starting to look somewhere else we have a baby (6months) and I'm pregnant again (13 weeks), but lately he seems quiet alot like he says he's fine when I ask him if he's OK but I don't know he just don't seem himself, it may play a part the fact that I just don't want sex I'm not off my partner I really love him but I've been like this since I can remember I just don't have a drive for sex for some reason,