Does it sound like my boyfriend finishes inside me?

How do i know if my boyfriend finished inside me? Can you feel it when he cums in you? We was making love last night and after a while he pulled out and asked me for a blowjob while I was giving him a blowjob there was pre-cum that got in my mouth. Than he put his penis back in me and we started making love again like 5 minutes later he Moans and then he starts going fast and then he stops and stays in me a few seconds and then we get up. He is breathing fast! I felt something trying to drip out of me but it didn’t if that makes sense! I felt down there and there was some fluid that wasn’t sticky and I know I didn’t have a orgasm. He tells me every time we make love that he does finishes inside me. But it doesn’t drip out when I stand up. I know when my ex’s and have had sex it did drip out. My boyfriend has 6 kids and I have 1 so I know we both can have children. When I asked him why doesn’t it drip out of me he said because his cum is thick! I am on birth control but we also agreed if i would to get pregnant then we would be happy but we ain’t trying! I ask him why didn’t he finished inside me He tells me he did and that he always cums inside me.