It does obviously make it harder, but I never resented him for it and always stuck by him - I think if you love them you can't do anything different. (The reason our relationship fell apart was because he started lashing out and being a complete arsehole to me.) Just make sure you don't put ALL your worries and troubles with him; obviously he should be there for you but talk to other people as well because otherwise it might be too much pressure on him. I was under a lot of pressure until I convinced my ex to get help.
Also, make sure he knows he's nothing to do with the reason you have suicidal feelings - because I know it's easy for the partner to feel guilty about it. (e.g thinking they're not good enough or not helping you enough)