Nope nothing to worry about whether you have the stitches by the side or not. Basically the torn on your first child could be baby's head/body big, so when you give birth it causes the tear. It could also be because of vacuum assisted/forcep hence the tear. Otherwise, it depends on what other reason that causes it during your first born delivery. It does not affect our sex life except that if your vaginal too dry during intercourse after confinement and you would like to make love, then you are advice to use lubricant.
Wow! I would wish to give birth without cutting and stitching. May i know what you practiced? Like is it you did alot of walking and squatting?