If a Muslim wears clothes that are shared between him and disbelievers, and he only wears them because disbelievers wear them and out of love for them, is he thereby considered a disbeliever?

Imitating disbelievers in dress does not lead to disbelief (kufr). However, one might incur sin if the intention behind imitating them in clothing is out of love for them and to resemble them in their disbelief, particularly if wearing clothes specific to them. If there is no inclination towards disbelief, then such imitation is considered forbidden (haram) but not disbelief. For an act to be considered disbelief, it must be done with the intention of imitating them in a symbol of disbelief. As for loving disbelievers, it is not forbidden if it is due to kinship or worldly benefit. However, it is forbidden if it is for a religious reason, as Allah Almighty says: "You will not find a people who believe in Allah and the Last Day loving those who oppose Allah and His Messenger."