Semen not going in completey

My hubby who I love is on the smaller side some position are tough especially during my 3 fertile days when I’m really wet. We had sex on peak. he said he finished inside of me. When he cums his penis instantly gets soft and goes back down which makes it slips out. That’s why I’m like ugh did you finish in me 😂😂

This time He finished half of it inside of me and I gave him a bj to get what was left out. I was tired We’ve been ttc for two months now could him not ejaculating everything inside of me be the cause for delay

P.s He’s not doing it on purpose both on the same page these past two times it’s been me on top I’ll switch it to missionary😂