Business husband is acting smart & showing all expenses ....

you need to prove that by evidance and you can call the compnay owner as witness. He might be having percentage for such things and you can find that by calling the CA or Auditor of the compnay as witness.

he is also the co-owner and all people are at his side.

Still during cross examination the witnesses has to vomit the matter

Get his company record summoned and also his income tax returns and his pass books of all accounts.  Even the director of a company will not do any thing without remunertion.  If he keeps it secret that how much amount he is drawing as director of the company, taking into consideration of company activities, the court will presume his ernings and give you handsome amount as maintenance.  Do not worry.

A Single Judge of Delhi High Court in the case of Bharat Hegde v. Saroj Hegde, reported at 140 (2007) DLT 16 had culled out following 11 factors, which can be taken into consideration for deciding the application under Section 24 of Hindu Marriage Act, relevant portion of which reads as under:

xxx  Unfortunately, in India, parties do not truthfully reveal their income. For self employed persons or persons employed in the unorganized sector, truthful income never surfaces. Tax avoidance is the norm. Tax compliance is the exception in this country. Therefore, in determining the interim maintenance, there cannot be mathematical exactitude. The court has to take a general view. From the various judicial precedents, the under noted 11 factors can be culled out, which are to be taken into consideration while deciding an application under Section 24 of the Hindu Marriage Act. The same are:

                    (1)      Status of the parties.
                    (2)      Reasonable wants of the claimant.
             (3)   The independent income and property of   the  claimant.
4. The number of persons, the non applicant has to maintain.

(5) The amount should aid the applicant to live in a similar life style as he/she enjoyed in the matrimonial home.

(6) Non-applicant's liabilities, if any. (7) Provisions for food, clothing, shelter, education, medical attendance and treatment etc. of the applicant.

(8) Payment capacity of the non-applicant. (9) Some guess work is not ruled out while estimating the income of the non-applicant when all the sources or correct sources are not disclosed.

(10) The non-applicant to defray the cost of litigation. (11) The amount awarded under Section 125, Cr.P.C. is adjustable against the amount awarded under Section 24 of the Act.

Further it has been noticed by the Courts that the tendency of the spouses in proceedings for maintenance is to not truthfully disclose their true income. However, in such cases some guess work on the part of Court is permissible.

The Supreme Court of India in the case of Jasbir Kaur (Smt.) (supra), has also recognized the fact that spouses in the proceedings for maintenance do not truthfully disclose their true income and therefore some guess work on the part of the Court is permissible. Further the Supreme Court has also observed that "considering the diverse claims made by the parties one inflating the income and the other suppressing an element of conjecture and guess work does enter for arriving at the income of the husband. It cannot be done by any mathematical precision".

Although there cannot be an exhaustive list of factors, which are to be considered in guessing the income of the spouses, but the order based on guess work cannot be arbitrary, whimsical or fanciful. While guessing the income of the spouse, when the sources of income are either not disclosed or not correctly disclosed, the Court can take into consideration the following factors:

             (i)     Life style of the spouse;

             (ii)    The amount spent at the time of marriage and the manner in which marriage was performed;

(iii) Destination of honeymoon;

(iv)    Ownership of motor vehicles;

             (v)     Household facilities;

             (vi)    Facility of driver, cook and other help;

             (vii)   Credit cards;

             (viii) Bank account details;

             (ix)    Club Membership;

             (x)     Amount of Insurance Premium paid;

             (xi)    Property or properties purchased;

             (xii)   Rental income;

             (xiii) Amount of rent paid;

(xiv) Amount spent on travel/ holiday;

(xv) Locality of residence;

(xvi) Number of mobile phones;

(xvii) Qualification of spouse;

(xviii) School(s) where the child or children are studying when parties were residing together;

(xix) Amount spent on fees and other expenses incurred; (xx) Amount spend on extra-curricular activities of children when parties were residing together;

(xxi) Capacity to repay loan.

14. These are some of the factors, which may be considered by any court in guesstimating or having a rough idea or to guess the income of a spouse. It has repeatedly been held by the Courts that one cannot ignore the fact that an Indian woman has been given an equal status under Articles 14 and 16 of the Constitution of India and she has a right to live in dignity and according to the status of her husband. In this case, the stand taken by the respondent with respect to his earning is unbelievable.

a simple query -

How to deal with a husband who live his life & spend, showing all as his business expenses ?

Already replied that you need to gather evidance and prove by witnesses.