My ex is living with her new boyfriend; can I stop paying spousal support?

Maybe.  

Experienced Bay Area Family Law attorneys will tell clients that In California, if a supported spouse is living with a non-marital partner, there is a rebuttable presumption that there is a decreased need for support under Fam C §4323(a).  What this means is that the burden of proof is on the supported spouse to show that, despite the cohabitation relationship, her need for support has not decreased. 

 
 In Marriage of Bower, the Court found that “[c]ohabitation may reduce the need for spousal support because ‘sharing a household gives rise to economies of scale. Also, more importantly, the cohabitant’s income may be available to the obligee spouse.'” 
To raise this issue with the Court you do not need to prove that that your ex has a boyfriend, but you must show that relationship has to be more than a roommate/boarder arrangement meaning that either there must be a sexual relationship or a homemaker-companion relationship. Marriage of Thweatt.  And while you may not be able to stop paying the entire amount of support, you could substantially decrease your monthly payments.

Do I have to pay spousal support Under Federal Immigration Affidavit of Support?

In San Francisco Bay Area, many of my clients have sponsored their spouses naturalization process or green card process in the United States. Just getting a divorce does not necessarily change your green card status, but it may impact your support obligations. 

When a U.S. citizen seeks to sponsor an immigrant (including a spouse), the sponsor is required to sign an affidavit of support that includes an agreement to maintain the immigrant at an income level no less than 125 percent of the federal poverty level. 
The Federal  statute provides that the immigrant may file a federal suit to enforce the sponsor's obligation under the affidavit of support. What this means is that even if you do not have to pay spousal support, you may have to pay support under federal law. 

 In Lui v. Mund, a federal court found that an immigrant wife's failure to seek work, which a Wisconsin court had required as a condition for spousal support, did not relieve her ex-husband of his obligation under the affidavit of support that he had signed to sponsor her as a permanent resident in the U.S. 
Speak to a family lawyer or immigration lawyer if you are considering divorcing and you recently completed the green card process.

What impact does the amount of time I see my children have on child support?

The California child support calculation considers the percent of time the child spends with the higher earning parent. This chart helps calculate the timeshare component into a percentage.  

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Worried about your spouse making support payments?

If your spouse is no longer employed, it may be challenging to collect spousal support. However, Bay Area family law attorneys will tell clients that the Court can order the supporting spouse to provide reasonable security for the payments they have been ordered to make. Family Code Section 4339.  Reasonable security can include maintaining life insurance for the benefit of the supported spouse on the life of the payor in the form of a trust or annuity.  Another option is that the court can order a lien of limited duration on a supporting spouse's separate property to secure the payment of spousal and child support.  

Why does California have community property?

Does community property seem crazy to you? Bay Area Family Lawyers may explain to their clients that Community Property dates back to 1849 when the California Constitution established a civil law based community property system under its Constitution.  The Constitution stated:  "All property, both real and personal, of the wife, owned or claimed by marriage, and that acquired afterwards by gift, devise, or descent, shall be her separate property; and laws shall be passed more clearly defining the rights of the wife,  in relation as well to her separate property,  as to that held in common with her husband. Laws shall also be passed providing for the registration of the wife's separate property. "

And 1850,  California created law setting forth a community property  system.  Weird, right? Community Property law has undergone a lot of changes since 1850 - but the basic tenant remains the same. All property acquired during marriage - is community.