Henry the Young King going against his father's wishes here is going to be in a very bad way very quickly.
If Philip dies without male issue, or Louis does for that matter, this thread seems relevant:
WI: He had died on the Third Crusade and his son also dies in infancy. Would the French impose Salic Law? Who would his successor be?
www.alternatehistory.com
Going by primogeniture and not by any other standard (like Salic Law being brought up), the candidates with no male issue of Philip (and Louis's line dying out) are:
Marie's descendants (see the counts of Champagne)
Alix's descendants (see the counts of Blois)
Margaret's descendants.
etc.
I mean, HTYK frequently DID go against his father's wishes, and had his brother Geoffrey's support in so doing.
So, under Salic law, the house of Dreux is in line before the Plantagenets, and without it, Champagne and Blois get there first. Either way, it's not going to work out, and any Plantagenet attempt to take the French crown is going to end up in a futile, bloody war, potentially lasting for decades... oh yes, where have we heard that one before?!
So, we have four options as regards HTYK's marriage.
1) Marguerite, who remains fertile.
2) Failing that, her sister Alys. However, at this point Rome is trying to push Henry II to marry her to Richard, to whom she is engaged. However, it seems the old git was likely bedding her himself and that a child may have resulted, and certainly neither Richard nor his mother (acting on John's behalf) wanted any marriage to her to go ahead.
3) Ida of Boulogne. Geopolitically advantageous, perhaps, assuming the church doesn't nix it.
4) Mabel Fitzwilliam of Gloucester. Gives Henry domestically influential in-laws and helps prevent the Barons' War.
In either of the latter two cases, there are two ways it could happen. One, Marguerite dies. Two, as per OTL, HTYK pursues and obtains an annulment on the grounds of her infertility following the failed attempt to produce an heir.