Article 36 provided the grounds for annulment of marriages in this wise.
Art. 36. A marriage contracted by any party who, at the time of the celebration, was psychologically incapacitated to comply with the essential marital obligations of marriage, shall likewise be void even if such incapacity becomes manifest only after its solemnization.
Furthermore Article 45 provides that marriages may be annulled in this wise
Art. 45. A marriage may be annulled for any of the following causes, existing at the time of the marriage:
(1) That the party in whose behalf it is sought to have the marriage annulled was eighteen years of age or over but below twenty-one, and the marriage was solemnized without the consent of the parents, guardian or person having substitute parental authority over the party, in that order, unless after attaining the age of twenty-one, such party freely cohabited with the other and both lived together as husband and wife;
(2) That either party was of unsound mind, unless such party after coming to reason, freely cohabited with the other as husband and wife;
(3) That the consent of either party was obtained by fraud, unless such party afterwards, with full knowledge of the facts constituting the fraud, freely cohabited with the other as husband and wife;
(4) That the consent of either party was obtained by force, intimidation or undue influence, unless the same having disappeared or ceased, such party thereafter freely cohabited with the other as husband and wife;
(5) That either party was physically incapable of consummating the marriage with the other, and such incapacity continues and appears to be incurable; or
(6) That either party was afflicted with a sexually-transmissible disease found to be serious and appears to be incurable.
Legal Separation may be filed in accordance with article 55 with the ff grounds
Art. 55. A petition for legal separation may be filed on any of the following grounds:
(1) Repeated physical violence or grossly abusive conduct directed against the petitioner, a common child, or a child of the petitioner;
(2) Physical violence or moral pressure to compel the petitioner to change religious or political affiliation;
(3) Attempt of respondent to corrupt or induce the petitioner, a common child, or a child of the petitioner, to engage in prostitution, or connivance in such corruption or inducement;
(4) Final judgment sentencing the respondent to imprisonment of more than six years, even if pardoned;
(5) Drug addiction or habitual alcoholism of the respondent;
(6) Lesbianism or homosexuality of the respondent;
(7) Contracting by the respondent of a subsequent bigamous marriage, whether in the Philippines or abroad;
Sexual infidelity or perversion;
(9) Attempt by the respondent against the life of the petitioner; or
(10) Abandonment of petitioner by respondent without justifiable cause for more than one year.
Hope this might help.