unhappy..conflicted.. please help.

we have a 4 month old, but I feel like I'm falling out of love.. I was debating on leaving him before I even got pregnant.. it's like I do love him but this relationship is just doesnt feel like it's working for me. Believe me, I communicate my concerns constantly and he'll say "I'm trying" but he really isn't, it's like his way of blowing it off. I feel so bad. I wanted my baby girl to have a family that was together 😭 but I feel miserable. I know if I break it off I'll be heartbroken but I think in the long run I could be so much happier. any advice..? I feel so much guilt about this and I feel so conflicted it's like my head is spinning