Relationship between Othello and Desdemona and its progression through quotes

Throughout the play Desdemona refers to Othello with respect. 
Othello also has much respect and love for Desdemona but as the play progresses his language changes.

Act 1:2

Desdemona

‘my lord’

Othello

‘this fair lady’

Act 2:1

Desdemona

‘dear Othello’

Othello

‘my fair warrior’
‘my soul’s joy’
…