Relationship advice isn't my territory, but you'll have to tell him eventually.

Anyways, without 245(i) you will not be able to adjust via marriage to a permanent resident, in this case you'll need to wait for him to naturalize first before you'll become eligible for AOS.

The issue here isn't backlog, the issue is that statute prohibits AOS in any preference category after an overstay or working in US illegally, with exception of immediate relatives of US citizens (parents, spouses, and unmarried children under 21).