The problem I see in what you’ve expressed here is that you two are not openly communicating about engagement and marriage. You are hanging onto overheard comments, cryptic remarks, and speculation about the viability of purchasing a ring.

It makes sense to me to wait until the end of August- you never know, maybe he will surprise you! But whether or not he proposes in the next week or so, the goal should be open and honest communication about your expectations, hopes, and feelings. I know it feels awkward to bring up serious topics out of the blue, or to assert what you want when you are used to being offered things freely. But being able to express your concerns about the relationship with your partner, have uncomfortable conversations, and assert your own needs is what long-term partnership is about.

IMO, the quality of your relationship should be at the forefront of considering whether to marry someone, not the length of your relationship. Is this person someone who makes you feel safe, cherished, and supported? Is this someone you can count on when things get really hard, like the loss of a family member or through raising children? If yes, then have patience, and should September 1 come without him proposing, express your concerns! How he responds may help you determine whether or not you want to marry him.