Congratulations on successfully growing tomatoes from seed! :)

Looking at your picture in the other posts, I think there could be three reasons for that. Over watering could definitely be a problem. Tomatoes prefer moist soil but they don't like it to by soggy at all times. Also, the soil drying out in between waterings can be stressful for plants. Though, I don't think that's your problem.

Sun scald could be another problem. Where did you grow them inside? Under grow lights? In a bright window? When you do put them out is it in full sun? If so, it might just be a bit too much for them at first. When I harden off my tomatoes, I usually let them get some morning sun and then move them into the shade.

And third, I'm wondering if it's a fertilizer issue. You mention that you fertilize every other week, which seems a lot to me. What kind of fertilizer are you using? Maybe there is some kind of imbalance. I don't fertilize my tomato plants until I plant them out. Though, I do grow them in a compost/garden soil mix, which I would like to believe is full of nutrients. :) With purchased potting soil, I would check how much fertilizer is already in the bag and then add some granulated fertilizer about halfway through the plants being in the pots and putting them outside.

So, to sum up, I would suggest not fertilizing again until you plant them outside, watering a bit less and making sure they are not in full sun all day when you put them out.

I also tend to belies TOO MUCH watering and fertilizer deficiency to be the cause(s).
I am not into organic fertilizing but I gather that it is not as readily available to plants as synthetic ones.

Here is what I would do:

--- fertilize with water soluble plant food (rich in Nitrogen).
--- cut down on watering. ( 5 to 7 days apart should be fine).
More plants suffer from over watering than under watering.