was sex unappealing to you during pregnancy?

i am 18 weeks an for the past couple of weeks sex has just seemed to be competly unappealing to me. i mean it doesnt even cross my mind anymore. its partly because i am getting bigger and i feel alot less attracrive. and part of it is i just dont want to. my fiance is getting really irritable because i just dont want to do it but he just doesnt understand how i am just never in the mood anymore. i mean just a few weeks ago all i wanted was sex but now it just seems tiring.