You cannot do this. Your father Aonghas Og didn't fight at Bannockburn for nothing. Siding with the English now could be detrimental to not only your mission, but the mission for a united Scotland away from English domination. Look at the wider picture.
Opt out of any alliances. You're fed up pleasing other monarchs and leaders. Part of your mission is to achieve independence and liberate Gaelic culture. Break any bonds and form your own kingdom in the west .
You marry Robert's daughter Margaret. This is a strategic political alliance. Robert is a follower of his grandfather Robert the Bruce's cause. He recognises the importance of the Gaelic community. This alliance could be beneficial in the future.
Which card will you play?