Is my wife having a lesbian affair her friend?

[J.]

Married for 3 years, 2 kids (2.5 year, 1 year). Known my wife for 8 years. Lately she's changed a lot. She avoid sex , in the last 4 months , we've had sex 3 times only. She says she's tired, she goes to sleep early. When she goes to work she dresses very sexy, skirt, thong...etc. At home, she's more conservative. She's very close to one of her co-worker. When she's home, she'd text her, hit her up on social media. Lately, she would find excuses to go see her at her second job, saying that she's going to buy something. What is supposed to be 15 minutes changes into an hour and 15 minutes. I found out that she lied to me at least twice just to go see her friend. I don't know if she's having a lesbian affair or she uses her friend as a cover up for an affair with a guy, but something is up. Her friend has a boyfriend. My wife never gave me a hint that she might be a lesbian, she's actually hint that she didn't like that "lifestyle". She's a great mother, show off our family picture on social media and would like to have another child in one year or two. My problem is the lack of intimity( she actually avoids me), the lies when she doesn't need to, her "obsession" with her lady friend (who's 10 year older than her). I am gonna sit down and have a talk with her. What do you guys think, is she having a lesbian or otherwise affair. How should I confront her? Thank you in advance.