Feeling lonely

Hello all.
Please forgive me if I go on a little - I need to rant.

I have been in my current Relationship 20 years, he is my First true love.
None of us have never been unfaithful.

We have 3 children, our youngest is 19 months old. When I found out we was exspecting our 3rd we was so excited and couldn't wait the trouble is I know that means no intimacy for the duration of the pregnancy, he has a problem with it.
The thing is we have only had sex Once since our child was born, (27 months no sex)  it's also got to where he's sleeping on the couch (3.5 months) he makes excuses the bedroom is too hot, the fan is too loud.
I try and ask him is everything alright & told him I feel so lonely.
His reply sorry what did you say.
He's a fabulous dad to our kids, but I dont know how much longer I can carry on like this.
I love him so much him & the kids are my world... I'm so lost.

Any advice would be much appreciated - please no nasty comments or nasty remarks has they will be ignored. 

Thank you for reading. X