Self confidence

I feel like my husband isn’t attracted to me anymore since I had our second baby (the dec 2019 one). He denies that, we do have sex, but something feels so off. When I bring it up he says it’s all in my head and nothing is wrong & he’s attracted to me & loves me. Why do I feel this way then? He’s in the best shape he’s been in … maybe 8yrs?! He gets to work out 4x a week. I’m naturally thin but just feel blah and feel like my body changed so much since the 2nd baby vs the first baby. I can’t find the time to work out like I used to. Idk- is this normal to feel this way? I’ve been really down about our relationship lately and getting paranoid something is wrong. Is it just lack of self confidence?! I could really use advice.