Can I or my friends surveil my spouse?

You can try, but it is rarely successful. The way the human eye recognizes a person is by their body profile and distinct movement. Your spouse is intimately familiar with both ,so things like borrowing cars and wearing hats rarely do anything to conceal your behavior. If you are caught, you may risk some bodily injury. Also, there is always the issue of credibility since you and your friends obviously have a vested interest in the outcome of the case. Under current Texas law, you may also run the risk of a harassment charge or make it easy for your spouse to obtain a protective order. It is always best to hire a professional like BIA.