No intimacy

So me and my other half have been together a few years and have a baby together. Our sex life has gone downhill since I was pregnant and since having baby it’s even worse. He won’t even kiss me now without me initiating it. I try to initiate sex and all I get is excuses. I’ve tried talking to him numerous times and he just says not in mood. I’ve started back at gym and lost 2 stone of baby weight and he still won’t look at me. Really don’t know what to do about it now