I need sex ASAP

So I have been with my SO for almost 4 yrs & we are currently 25 weeks into our pregnancy with our first baby. We haven't had intercourse in about 4 mths & this weekend I insinuated myself to him because I have been really horny lately but he told me he felt weird & as if he was being disrespectful to the baby. Has anyone else experienced this? Should i be worried? HELP !