Partner with mental illness

Hi all,
Iam in need of some advice of who has been we're I've been, I've been with my partner for 2 years we have both come from nasty relationships with 3 children each. After a long year of tears and frustration I said to my partner I know there's something wrong I myself have suffed depression and suicde so I knew this was his problem. Thankfully he has been to the doctors and has been given anti depressants. I have been through a lot in my own life so I asume and know Iam a strong person but the one thing I can't handle is his mood swings I suggested to the doctor about BI Polar and there is some strong signs but my partner doesn't thinks so. So going off a dignose of bi polar how do the ones who love them the most stay strong? I feel so broken he is such a beautiful person with a big heart under it all but his happy when things are good then things are bad his so low angry rude.. please can someone help give me advice to keep strong I see a councler myself but not to often due to work and family commitments. I love him so dearly but his additide is so negative he just doesn't give a f about anything... Iam trying my best to stay strong and I won't give up on him as I know what's under it all the person I met 2 years ago. Please any advice would be great to help me
Thankyou so much