IMO leave it. As many here would say, she's fired you as her husband. Don't buy her presents. The thank you was enough. Maybe it'll give her some food for thought if you don't get her something and you don't let her getting you something make you feel guilty for not reciprocating.
Sounds like you still had a good easter with the kiddos! Congrats.
M:26 H:32 T:8yrs ILYBNILWY/ "I'm not happy": 2/6/16 D-Day-discovered PA/EA: 2/10/16 Separated: 2/14/16 He's living with OW I moved to different state: 06/16 Currently: Trying to move forward