Slipping out

Brittany • 20. Married to my best friend. Puppy enthusiast.
Okay ladies I need some help. I am engaged to my best friend and we recently started having sex. Both of us are bigger people. Due to his size, he isn't endowed length wise. This causes some frustration in the bedroom because he sometimes slips out easily and we have to take time to readjust. Any tips on helping reduce falling out? 😅 Thanks in advance. 😊