My partner lies to me and I don't know how to approach it.

I don't know who to turn to with this, so I'm entrusting reddit with it and hoping you guys can help me out.My partner and I have been together on and off for a few years and there's a reason it hasn't been one solid run. I love them dearly, I do, but there's certain things we cannot see eye to eye on and certain behaviors they repeatedly engage in that I repeatedly ask them to stop and no effort is made. Lately we've been making it work pretty well but I'm having trouble overlooking the lying!I am 99.99% positive these things are lies because half of them are just impossible (they try to one-up me in our sport, which I am training them in and am far more experienced in/better at, and will tell lies that don't add up to their current skill level e.g. "I was training police horses when I was 9 years old," "I owned and trained broncs when I was 8," "I learned how to ride and ride much better bareback/tackless," etc. , and half of them are peacocking exaggerations I know never happened such as "I was an MMA fighter in middle school," "I was stabbed in middle school", and frequent "I punched him in the face/yelled at him to stfu/stuff their teacher did that a teacher would never do/etc." We're relatively separated physically right now hecsuse of my health so we play a lot of getting to know you questions type games to stay connected when the conversation dies and I've mentioned in my answers a few times that liars and lying absolutely disgust and turn me off and i hate nothing more than dishonesty, which my partner will agree with me on, but the behavior hasn't stopped.This is also a partner who takes my health problems on themselves sometimes for fun or to compete or something wothout knowing what they're talking about, which is another form of dishonesty, but when the time comes that I need help I could not be more blessed; they will and have taken care of me night and day and they've already stayed they don't care if I'm this sick the rest of our life. "Their" illness only occurs when I don't need anything myself and never interferes with me. But again, it's lying! (As an example, we were talking about my Bipolar I disorder the other day and they were saying 'oh yeah, I have Bipolar II because I tend to lash out at other people more instead of turn it inward (not what it means); so I explained that Bipolar II patients have more mild and subtle symptoms and can still carry on theor lives, whereas someone like me with BDI can go through extreme extreme cycles and episodes of psychosis and led to a number of hospitalizations and two violent crimes in my you ger life. And immediately my partner switched definitions of BDII and was like, "oh, yeah, I can still go on with my life, that's why I have type II." It's bullshit. I agree they have something lsychologically wrong but I': hazard a BPD guess judging by a lot of the behaviors I see all the time.But anyway. That's beside the point.How do I address the needless lying? It makes me feel like I can't trust a thing my partner says. They say they can do this and that and I don't know what's true anymore! But I know if I say anything the same thing that always happens when I try to bring up a problem will happen; they'll blow up and overreact, we'll break up, they'll get morose and suicidal on me, and then a few months of not talking later we'll end up being friends again and soon after getting back together with the issue unresolved.Any advice from people who maybe have dealt with chronic lying before?