As you can imagine this has really messed with my head, but I’m thinking that was the intent.
Two weeks can't undo twenty years. As is often remarked here, promises and brief changes mean little, what counts is real change over extended time.
Sure, you caught his attention but is it sincere? We can tell you the odds whether his sincerity lasts very long - for all we know he might be an exception - but it's your judgment that counts more than ours as to whether your spouse will actually reverse his life and behavior patterns. What does your gut tell you?
Sure, many will sweet talk of promising changes, others will do the reverse, ranting, raging and pressuring - called Extinction Bursts - but without the meaningful involvement of professionals such as therapists then all too soon the person reverts back to prior patterns, the spouse's prior "comfort zone".
On a practical basis you can't keep your spouse on some sort of probation indefinitely. Ponder that. Meanwhile, a person with BPD (pwBPD) has an exaggerated sense of self, so be alert to subtle indications your spouse may be preparing to set up a golden parachute for self or laying the groundwork blaming you for the marriage's demise.
