I do think having a relationship is lovely. I am married almost 30 years. BUT that being said, he doesn't really understand the blues...he even gets pouty if I am up on the computer with my light box and not ready to go run around doing things with him...I expect that will get worse in his retirement.
so while having someone is nice, it is also more work when you may least feel like having to try...best solution? fall in love in the good time of year and then work hard to make it last thru the bad times.
Sounds like you do wonderful things for yourself. keep on loving you and the right person will come into your life. No one person can be the solution to our problems, but the right person couldn't hurt! :)

Welcome Natalie, I sympathise with you, I am in the southern hemisphere and my SAD lasts from march-april through into october, it is a very long season and can feel like forever!!
I have a wonderful husband who I met around the time I was first coping with fullblown SAD.

I don't mean to offend, but I sometimes don't express myself too well over keyboard, so here goes: I'm strongly of the opinion that its not fair on anyone to expect a relationship to fix any issues I have. Its not fair on me, because if that person leaves I haven't learnt any coping strategies, and its not fair on them, its just too much pressure. I think it can create dependencies as well.
With this in mind, I worked really hard to get myself into a good place mentally and develop coping strategies before I started seriously dating, and I was careful "not to let my issues get in the way of our relationship"

Now he knows what goes on with me with the seasons, and his support with practical things when I'm down helps. However, I know I have the coping skills I need if I'm ever without him for a time, and as Blueviolet said, it can take a lot more work when you least feel like putting it in.

I think I've waffled a bit here, I hope you can get something out of it

I think when we are hurting we tend to look for other people to help us regulate our moods and calm our pain/discomfort. I do it too, though not with romantic relationships. It's important to keep in mind, though, that honest relationships are also a source of pain and discomfort. They tend to challenge us on a deeper level than with friends or co-workers. Stuff that's been buried often comes up once you are over the infatuation phase. Infatuation is like a pep pill...it makes us feel energetic, fun, funny, happy, connected. Our endorphin levels rise, much like with exercise (good for you for exercising when you'd rather sleep!). It has itspurposes, for sure. But I wouldn't recommend it as a treatment for SAD for several reasons. First off, there is other stuff that comes with relationships that can make you SADder. For treatment of SAD, I'd recommend you talk to a health care professional, be it a counselor or psychiatrist. Usually a combination of treatments like prescription medication, light therapy, exercise and talk therapy work best for most people. I recommend a light box called SunTouch Plus by Nature Bright, after a lot of research on light boxes. I've been using it two winters. Best of luck to you in your journey toward feeling better. Keep exercising. Get together with supportive friends. See a professional. That's my best advice to you.

I think it's true that it's hard to expect a relationship to "fix" deeper rooted issues that you will probably deal with for a long time. That being said, the support of an understanding, supportive person can help to buoy you up in times of hardship. But you also need to have some coping mechanisms in place that come from within yourself.
Light boxes are very useful, I just started therapy, which has been very fruitful, exercise always is helpful, so I'm glad to hear you're doing that.
You should talk to your talk about taking extra vitamin d. I have been doing that and it has helped TREMENDOUSLY!

I know personally that having my boyfriend has helped some but at times I find it hard because he does not fully understand what I feel and how hard the weather/seasons do effect me. This frustrates him because he wants to help but can't which in turn frustrates me. I just end up telling him that knowing that he is there for me and loves me is good enough, which makes him feel better too.
So while having someone does help, i feel that having good coping skills is the most important thing that can help those with SAD. When I am feeling down because of the weather I just distract myself with music, TV, video games, or anything really that keeps me oblivious to the weather (I even sometimes close my blinds). In addition I find that looking at the weather channel and counting down the days till sun comes again helps me fight the symptoms too.
Nevertheless it sounds like you have great coping skills already and good plans at keeping yourself busy. Most importantly do remember that you are stronger than you think you are and can get through the roughness alone or with someone.
With that said I agree with blueviolet's post. Keep loving yourself and give yourself words of encouragement (perhaps make a list of encouraging words/phrases and say them before bed and in the morning). When that special someone comes into your life, which they will don't you worry about that, it will be wonderful and hopefully they will be an extra form of support to get you through the dark days. You can do it!!! ^_^