At 105kgs, I've broken lines, masts, booms, and flattened the deck on my board, I feel your pain Leman! Although, if you're that hard on your gear, I wouldn't be too worried about your lines, more the technique? If you're putting a lot of weight on the harness when jumping, you're better off breaking harness lines, than getting indestructable ones...and breaking, or bending your boom...lines are cheaper!
I'm currently using North fixed lines, haven't broken one yet.
As for Easty's comment... you're right!

The first few breakages I had, I called the suppliers to ask how it happenned, and got the question "how much do you weigh?" Once I tell them my weight, the standard response is "Ohhh, that would explain it then."