Stolen Love

Very similar premise and similar vibes, setting, and characters. In both:

+ leads are childhood sweethearts who promised to marry (or eloped in SL)
+ they are separated and ML goes off to war for many years
+ ML returns after military success
+ by the time ML returns, FL is married to someone else in his family and has a son
+ ML actively tries to steal FL while she's still married
+ there are scenes of ML getting spicy with FL while her husband is nearby
+ FL denies ML and repeatedly rejects & hurts him
+ very aggressive, domineering ML, assault warning for both dramas

The list goes on but I won't spoil beyond this. If you liked one, you are bound to like the other.

Both are mini dramas in which one of the leads believes the other is dead. Both MLs return after injuries and poisoned to find the FL married and with a young son, who unknown to him is the ML's child.