It's incredibly normal
Many people take the opposite role in the bed room, because consciously or subconsciously, they want what they don't get in the rest of their life, and can have responsibility taken away- or, if they're the opposite of you, they can be dominant and have power for once. The change is very appealing to some.
Or it could just be that by nature you're not very submissive, but doing so turns you on. There's nothing wrong with that either.
Do you mean scarring ligature marks, or just places where the skin's been cut into a bit, temporarily (like
this, either shallower or deeper? I wouldn't recommend going for scars, the stress that causes them is dangerous.
If you just meant the temporary markings, a chain (as shown) can leave marks quite easily without being left extremely tight- that picture is mine, and it's just from moving my legs (or having them moved) when Sir fucked me with my ankles tied. Rope can quite easily too, but I'd recommend not just tying it so tight you get marks, as that leads to cut off circulation and ropes that are much harder than necessary to untie. Instead, let them be used in a way they might be strained against. In theory, chain could be used tighter, since a quicklink or something similar can be released easily if it's too much or needs to be undone, whereas knots tighten and tighten.
When using rope or chain, you of course want to have a pair of bandage scissors (/other safe scissors) or a pair of bolt cutters ready, respectively, in case you end up needing them. Quick links and knots both jam.
Come to think, if skin irritation isn't a problem, you could slide the rope to get a rope burn effect that would resemble ligature marks as well. Just a thought.