Husband Doesn't Want Sex Anymore

So I'm needing some suggestions and input. Ever since I had my baby girl 18 months ago my husband doesn't want to have sex with me. Anytime we get intimate he loses his erection and asks for BJs instead.

He's a great dad and a good husband overall. He's a police officer and recently started working the night shift... my mind is going everywhere. Idk if it's just from his job, the hours, if there's someone else, or if I really just feel that horrible to him that he'd rather not sleep with me.

I just feel like, wtf is my life going to be like if the mf-er won't fuck me. Honestly, I just feel really shitty about myself right now, and idk how to fix this. I feel so self conscious. I'm sick of trying to have sex with him and feeling rejected.

Has anyone else experienced this? Any suggestions.