Struggling...

My bf and I have been together over 2 years now and have not had sex. Neither of us are virgins but my last relationship was abusive and it's been difficult being intimate. Thankfully he has been more than understanding. Recently I've decided I'm ready but when I bring it up, he always has something else to do or is too tired. It's been a couple months now of this avoiding thing and I'm getting insecure and worried. Advice??