Proper communication doesn't work like that. The fact that he is seen as bitchin', & the fact that they consider that a reason to be cheated on, shows immaturity from all sides.
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Both parties should be able to maturely state their grievances, attempt to understand their partner's viewpoint & where they come from (and while their point might not always seem valid or true, their feelings about it are still real), try and talk it out & find solutions or compensations where you can meet each other in the middle.
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If things are truly incompatible, break up with your partner rather than cheating.
Cheating just fills one gap in your current relationship. If you are unwilling to break up to be with the other person, either due to
(1) being comfortable in your relationship, or
(2) other benefits, or
(3) this is the only gap and you like your partner otherwise,
then you need to reassess your situation and find an overall more compatible partner, or work on your relationship / yourself.
.
Both parties should be able to maturely state their grievances, attempt to understand their partner's viewpoint & where they come from (and while their point might not always seem valid or true, their feelings about it are still real), try and talk it out & find solutions or compensations where you can meet each other in the middle.
.
If things are truly incompatible, break up with your partner rather than cheating.
Cheating just fills one gap in your current relationship. If you are unwilling to break up to be with the other person, either due to
(1) being comfortable in your relationship, or
(2) other benefits, or
(3) this is the only gap and you like your partner otherwise,
then you need to reassess your situation and find an overall more compatible partner, or work on your relationship / yourself.