It was established early on that neither of us date multiple people at the same time and that we will be/are exclusive.
But make sure you're being realistic about this assumption, and not just basing it in fantasy. If you're ever confused, just ask your partner casually.
When both of you know that you’ll be spending weekends together, or at least Friday and Saturday nights, you’re probably exclusive.
It’s one thing for him to tell the guys about his hot date or GF, but when he tells his closest female friends all about you, he’s getting the vote of approval and wants to share his joy. When he’s ready to let go of her and move onto a meaningful relationship with you, he’ll let his ex know he has a GF, so respectable boundaries can be set. When you exchange keys with enthusiasm he’s letting you know that you now have the key to his heart.
Jake and I saw differences between committed and exclusive.
We figured that exclusive simply meant that there was no hooking up with anyone else allowed: no making out, no dating.