What does Causative + たる mean?


The character girlfriend criticizes him and he says this:

> 俺が善がるだけしかできねぇってか!?

My reading is akin to "Are you say I only satisfy myself!?"

Then he later adds

> 死ぬほど善がらせたるわ!

From context I can gather he seemed to be saying he'll satisfy her needs to a
crazy degree. But I don't this use of causative + たる. たる seems to be used
after "noun" for capacity, but how is after a causative verb?

From context I can gather he may be saying "I'll show you I can also fulfill
you needs/take care of you/etc"

