What should I do?

Hi, I’m stuck, very very stuck 😢 I’ve been with my boyfriend 12 yrs, now we’ve both made mistakes we’ve both cheated I admitted to mine and he has yet to admit his even though I’ve proof but this all happened in the first 3yrs if ya being together, we’ve been together since I was 16, things moved very quickly and needless to say we’d moved in together just a month later, now other than those first few rocky years everything was great up until a year and a half ago 😔 he started staying at his brothers which didn’t really bother me until before I knew it he just wasn’t staying at home anymore, I don’t know how it got this bad now he comes home of a morning gets changed for work and leaves for work , he returns gets changed and leaves to go to his brothers, I see him for no more than 2hrs every day 😩 he’s got him self into debt, I’ve told him how lonely it makes me feel and hurt that he literally spends no time with me, I’ve even told him I don’t want to stay in our home anymore, it haunts me we have so many good memories here it’s an empty shell without him, could this be a mid-life crisis? I don’t want to throw 12 years down the drain but I’m at a loss as to what to do?! When I’ve told him to just pack his stuff and go he literally breaks down but I find I’m asking if it’s real or fake, I feel like I’m breaking I’m torn in 2 do I stay and try to help him or leave and help myself