Squirrel31 your child could resent not having a sibling or resent a new child. Speaking as mum to a teen they tend to resent a lot at certain stages!
Get counselling for you. What do you want. Do you want to work on your marriage, and of you do choose to, then go for it.
Yoir marriage needs to be strong to stand more kids. It's more work for everyone.
If you did ever love your dh and he loved you, there is hope I believe.
If he thinks you hate him and maybe all you want is another child, I don't blame him for feeling unlike sex.
Who is limiting sex, you or he? Or is no one instigating it?
Assuming he is not abusive and is a good bloke and you find him attractive etc all big assumptions! then sex might have a healing purpose in your marriage.
Can you put thoughts of baby 2 on hold for a few months and just try and fall back in love again?
You do not need to answer but how old are you and how old is your son?